[Lynn Eades]

Hello Mark,I'd say none had plain clear glass.
Firstly "MkI British Carrier" is a bit vague. There was a MkI of everything.
A MkI Bren, a MkI Scout, a MkI Armoured O.P., and an early MkI Universal all started with a (CAV/ Bosch light) with a diffused glass like you might find in an old bathroom window, here.
Later I believe the MkI Universal carrier went to a bigger dia. headlight (with a thinner rim and no door screws in the front at 3.00 and 9.00 o'clock) the door screw being at the bottom. These Lucas or CAV marked lights (also common to Loyd carriers and Valentine tanks)had glasses with vertical lines about 15mm apart, with the latest (most common here)type having vertical lines about 7 or 8mm apart.
Some of the mid era glasses have a Ford oval mark on them. Many on active service and I guess for homeland training were converted to, or were factory equipped with blackout lights. Some being painted black on the inside, save for the small half moon open centre.
The above is all just my opinion. Others may disagree (which is good when it helps to define the facts)
I understand you have Wolseley U.C's, so I assume they are in the T33,000/ T34,000 range. I do not know when the lights changed from the early style.