I've not seen a custard with a trumpet bowl before, so always possible that the handle has been added to what otherwise was intended as a small wine or dram glass. You don't give size - it is always useful.
As a general comment, jellies didn't have handles, custards did, but as always there are exceptions to the rule.
From what I can see on the underside of the foot, it looks possibly to be a form of circular snapped pontil mark, a type of scar produced by a hollow pontil rod, and I think more a Continental thing than British, but not certain of that. A good pic with the light slanting across the scar would be useful - plus a uniform dark background bearing in mind this is clear glass.
The top down handle appears to be saying pre 1860 ish, but always possible this was a later copy, although your comments about 'bits and bobs' would support a mid C19 date of manufacture.
This type of handle wouldn't normally be associated with the later shears marks.
Let's see what others think.