I need some help to find "the" bike

[Mr Gazza]

Of course DVLA would be able to match a reg to an owner in seconds, and the Police have access to that info too.
I don't suppose for a moment that they would tell you who owned that bike, but....

If you took the right approach at the right time, an amiable Policeman might... just might, contact the owner on your behalf and forward your contact details. It's probably highly irregular (or even illegal?) but might be worth a try?

I am fairly certain that DVLA would tell you the reg of the bike that your Father owned?
I think they will list vehicles owned by yourself historically, for a fee possibly.

It might be worth having a chat with DVLA to see how far you can go in that direction. Or wander into your local Police Station and not expect too much.

I am sure there must be some sort of search service that could be employed, such as the vehicle check that you can buy when buying a bike.

[Dirty]

Originally Posted by Mr Gazza

It's probably highly irregular (or even illegal?) but might be worth a try?

Yep, illegal and certainly not worth trying as even that could get you in trouble. There is no way of legally accessing either police or DVLA databases for your purposes I'm afraid.