I'm using bugeye lights on my Locost project.
The bugeye units are Lucas L549 for the tail lights, and L594 for indicators. Bugeyes use the L594 on the front also.
I think the L551 is correct for the indicators, but I think the L594 (bugeye) looks better. I might use something like the L551 for a high center brake light. "Correct" can be somewhat subjective on a 7, and especially on a replica.
Original tail lights had an angled plinth to fit the fender angle, depending on where you mount them on the fender