Definitely better off on BA from T5 as there is no terminal change- also they should be able to check your bags through to AMS (I think this is the case even if booked as two separate tickets). So much less stressful and much more prudent.

As others have said, the OP's itinerary is do-able, but IMO very tight with checked bags. Personally, I would want an extra 45 minutes to make it a more comfortable transit.