page from Flight International's archive shows BEA (H)'s main operating base to be Gatwick.
1965 | 2131 | Flight Archive
However Beccles (Ellough) Heliport was opened in 1965 by BEA to support the new gas fields off Gt Yarmouth - which seems more of a coincidence than can be ignored...
The first gas
discovery in the British offshore sector was on the Sole Bank in, I think, 1964, with the Leman following in 1966. Whether there would have been a need, let alone offshore facilities for such a large machine in those early days is more than I can say. Most machines then were S55 I think.