The marriage of William Glister in 18/8/1771 Calthorpe was to an Elizabeth Cook (not Roberts).
I think this couple are the parents of Thomas although as already mentioned Calthorpe baptisms are pretty scarce online.
They had a son George bp.2/2/1772 Calthorpe but I believe they then moved to Blickling where some children were baptised before returning to Calthorpe.
William bc.1746 was buried at Calthorpe 23/3/1802 (shown as married man).
Also burials of 2 daughters of William and Elizabeth at Calthorpe:
Susanna bur.19/6/1785 (no age given)
Susanna bur.24/12/1801 (no age given)
Have found 4 baptisms at Blickling:
William bp.10/3/1774, son of William and Elizabeth
Elizabeth bp.10/5/1776 dau. ditto
Susanna bp.30/5/1778 dau. ditto
Mary bp.2/1/1781 dau. ditto
Perhaps it was after these baptisms that the family moved back to Calthorpe.
Looks like William Glister senior was from Blickling too.
William Glyster bp.17/7/1747 Blickling, son of John and Elizabeth Glyster (alias Lyster)
There are other baptisms to John and Elizabeth (as either Glyster/Lyster) at Blickling and one entry states the family were 'late of Hanworth'.
Annette