That ain't bad Gary. Plus it means you can keep the Sterling barrel for a rainy day. As a matter of interest, you can also use a Sterling breech block in a Lanchester too. Just have to......... anyway you can if you need to.
Something else that'll improve a Lanchester. We used to find that they'd misfire on some issued 9mm ammo. The ammo techs used to say that it was the hard primers that would thwart the efforts of the separate striker (unlike the fixed striker in the Stens and Sterlings). Incidentally, George Patchett discovered this too when he was faffing about with ex Lanchester breech blocks and separate strikers in his early Patchetts/Sterlings. Fixed is best! Anyway, I digress....
To cure this with a Lanchester, break through the not very hard surface of the breech block and drill into the core where the large diameter striker block seats. Tap the hole and insert a grub screw and lock it down onto the block with the striker forwards. There it is, a 'fixed' striker. Never approved in service but for reasons best known to myself and a few others, a GOOD idea and improvement.
Can we see a few more pics of yours Vince?
Merry Xmas Gary and all the very best to you and yours.