Brian of nzolivers.com is descendant through Gilbert and Janet’s son Malcolm.

Information from “McCaul Family Scotland” compiled in 1991 by Marcia Barbara (Barbara) McCaul, Canada (b. 1932, d. 2002). Barbara was the great-great grandaughter of Gilbert McCaul (b. 1765) and Janet McFarlan (b. 1770). Brian of nzolivers.com is the great-great-great grandson of Gilbert and Janet.

Barbara writes:

Gilbert moved to Glasgow before 1793.
Boot and Shoe Manufactuers - and Manufacturers of Gloves. Gilbert McCAUL & Son(s)
Member of the Cordiners Guild
?1803 Gilbert McCall Shoemaker , Adelphi St.? (may not be same man)
1803/04 Gilbert McCAUL, Shoe Shop, 13 Hucheson Street
1809 Gilbert McCAUL, Shoe Shop 24 Hucheson Street
1825 Gilbert McCAUL & Son 35 Virginia Street
1829 Gilbert McCAUL & Son 35 Virginia Street
1835 Gilbert McCAUL & Son 35 Virginia Street
1839 Gilbert McCAUL & Sons 83 Hucheson Street
1840 Gilbert McCAUL & Son 83 Hucheson Street and 5 Garthland St.
(Wholesale Boot & Shoe Manufactuers)
Note: Glasg. Directory : 1801 George McCAUL, Shoe Shop, Hucheson St.
[Could this be a relation - or could "George" be a misprint in the Directory for "Gilbert"?]

Admitted Burgess of Glasgow and Guild Brother, [?15 Feb. 1793?] [Maltman?]
[Note: Did he in fact change occupations? Or is this another Gilbert McCall?]
Also entered as Burgess & Guild Brother - Cordiner

Married 28.3.1793 in Glasgow to Janet McFarlan, residenter of Glasgow. They were married by Mr. David MacGibbon, Minister of Buchanan, Janet's home Parish.)

Two portraits in possession of Canadian descendants of Gilbert McCAUL and of Janet McFarlan, his wife, dated 1830. Another one is of their daughter Agnes (Nancy) 1794-1880 who married John Hill in 1819. These portraits were almost certainly done by Daniel MacBrair, who was a portrait painter working in Glasgow at that time. The portraits came from the home of Gilbert John McCAUL, Creggandarroch, Chislehurst, and were said to be "grandparents." Miniatures of members of the family include at least one believed to be of Gilbert McCAUL (1765-1842) in possession of South African descendants.

Addresses for Gilbert McCAUL from Glasgow Directories:
Year Residence
1829 9 Cochran Street, Glasgow
1834 George St.
1840 270 George Street
1841 George Street (See Census entry)
1842 (Died) May 1842
Also ?date?: Adelphi St., Govan (or was this business address)

His widow died 1845 at Castlemilk Place, Hutchesontown, Glasgow, where she moved after his death. [Census checked for 1841: no McCAULs]

The Family Memorial and Burial Place (#38 St. David's, Ramshorn Burying Ground) of GILBERT McCAUL, CORDINER, GLASGOW 1825
Note: The date of 1825 refers to the date he bought the burial lair at Ramshorn.
(A photograph taken of the memorial by one of the New Zealand family, who had it restored.)

Gilbert McCAUL (died 23 May, 1842) and his wife Janet died 11 Nov. 1845 are both interred there as are some of their children; (listed in Lair Register); others are interred elsewhere but their names are inscribed on the Family Tombstone.
Style of Funeral: Shoulders; 6 ushers.
A copy of his Testament and Inventory on file.
He was a witness Entry in the Colmonell, Ayrshire Parish Registers for baptism of Gilbert McCall [sic] on 26 May, 1765. son of Andrew McCall [sic] and Janet M'Ilmorrow. We feel fairly certain this is our ancestor.

Note: in accordance with the Scottish Naming Pattern Gilbert's first son is named Andrew, after his grandfather, and the first two daughters Janet after their grandmother – the first one died as an infant, so the next daughter had to be christened Janet too.

Brian of nzolivers found:
Ramshorn Cemetery
https://en.wikipedia.org/wiki/Ramshorn_Cemetery
The Ramshorn Cemetery is a cemetery in Scotland and one of Glasgow's older burial grounds. It has had various names, both official and unofficial: North West Parish Kirkyard; St David's Kirkyard; and Ramshorn and Blackfriars. The latter name tells of its link to Blackfriars Church, linking in turn to the pre-Reformation connection to the Blackfriars Monastery in Glasgow.

The burial ground was used from 1719 to 1915. In the 20th century it was remodelled along the lines of the London Improvements Act, moving most stones to the perimeter to create a usable park area. Apart from some flat stones still remaining in-situ this has largely disconnected the stones to the actual spot of interment.

In 1824 the church of St David was built on its southern side, designed in a fine Gothic style by the English architect Thomas Rickman, with modifications by local architect James Cleland.

The cemetery is effectively in three sections: the original cemetery; an enclosed central walled area where the old church stood; and two small walled sections flanking the new church. Unusually monuments adopt only two forms: wall monuments and flat slabs, other than a small row of small 18th century stones upright but partly sunk into the ground, standing in a line to the north-east.

Despite its great simplicity, the majority of graves are to rich Glasgow merchants. The austere style is a hangover from Scottish Calvinist views.

Brian of nzolivers found:
http://www.happyhaggis.co.uk/lanark-ramshorn.htm
The family memorial and burial place of Gilbert McCaul, cordiner Glasgow, 1825. Gilbert McCaul died 23rd May 1842 in his 78th year, interred here. Janet McFarlan, his wife, died 11th Novr 1845 in her 76th year, interred here. Janet, daughter, died 1st Jany 1798 in her 2nd year. John, son, died 17th April 1830 in his 28th year at Antigua. Andrew, son, died 27th June 1834 in his 37th year, interred here. Jess Taylor, daughter, died 25th Decr. 1848 in her 49th year, interred in Necropolis. William, son, died 24th Novr 1861 in his 54th year, interred here. Jane Brown Reid, daughter, died 12th Octr. 1867 in her 58th year at Ayr. Agnes Hill, died in Stirling 17th Jany. 1880 in her 86th year and interred here. Elizabeth Burden Struthers Walker died 7th Jany 1881 in her 75th year, and interred in Old Gorbals Glasgow. Malcolm, son, died 18th Jany 1891 in his 87th year, interred in Necropolis.