RJS wrote:

I've also had a call this morning from a safe opening firm. They
explained that Leabank safes are no longer manufactured. They can
open the safe but it would be unusable after doing so - I'd need a new
lock afterwards and they wouldn't be able to open the combination
without the original key. However the cost of doing so would be more
than the price of a new, reasonable, domestic safe. They suggested
slicing it open just for curiosities sake!

If there's stuff in it, can you keep it?

I'd be inclined to try an angle grinder on the back of it, as it sounds like
it's worthless.