Sounds like a viable project providing:
the MWT's are above the low 20's,
the engraving is worn on soft metal, not hardened,
you are prepared to spend a LOT of money getting the work done right.

No, do not give it to Purdey, they will charge you a fee 5x what it would cost you through the best of the US restorers.
However, I would consider sending it to the UK for the work but I appreciate that this is a whole shed load of work.