Paul K
Your hours on the Beech will count towards the 500 Multi crew needed for the ATPL Issue, as long as it was in your companies AOC that the aircraft was operated two crew.
Its a grey area if it was private ops and you might find that you will have a problem convincing the CAA that it was two crew ops privately.
However as I'm sure you know, the ATPL cannot be issued until you have a Multi Pilot Aeroplane type rating on your licence.
Hope this helps