KTR,I've got 3 and will post some pics as soon as I can get them out. All are #3 pattern sporters. The last one aquired is a BSA LeeSpeed in 35cal (356 groove dia), unkn case and haven't had time to do a casting. Anyway, I pulled the bbl and replaced it with a No1MkIII 410shot bbl. Use it for Sunday morning skeet shoots and works perfectly. Even feeds the second round ,,well most of the time. Point is that the SMLE 410 barrel is the same profile as the original BSA sporter barrel. The forend fits it perfectly.
Also, the BSA top tang safety was an option only and not a necessity even with the Metford cocking piece on the bolt. The Metford cocking piece only gave the use of a half cock as a safety, no other safety device on the rifle. But that in itself was considered sufficient at the time in the hands of a competent shooter. The Lee Metford rifle in it's final form had no extra mechanical safety IIRC. I feel the Lee sporters & Mannlicher Schoenaur pre war sporters are some of the best if not the best handling rifles I've ever had.
I've got a Lee Metford buttstock where someone very carefully worked down a military buttstock to a shotgun profile, then checkered the grip. Proves that it can be done, if you're patient.Otherwise I will have to make one up from a military model...but who would do the custom wood? (That's a serious question).