I cannot answer your question directly but here is my experience…
I also have a Mk3 analogue only BV7/40. The “picture board” failed. It was replaced under warranty and then suddenly I had digital channels! I have often questioned whether there is a Sat receiver in there somewhere too? Short of connecting a dish and trying it I don’t know but via operation there is nothing to suggest that it is not there? It all behaves as if it is there. Unfortunately the digital freqs were changed a year or so ago so i have now lost the digital channels and of course there is no analogue so it is only useful for Chromecasting now?