They'd look great on a Morgan - would they be a straight swap?
Can't guarantee it, but as they are 7" headlights and so is a trad four wheeler they ought to fit one of those.
No idea what size units are fitted to a five speed three wheeler. Vintage twins have smaller lights than 7" and quite a few have modern 5.25" units - mine has.
Fitted as the ones it came with weren't original, perhaps from the 50's and used very hard to get bulbs. 
