I don’t believe there are currently flights to Bern from the UK that are direct. When I lived there and *A allowed some 29 sectors on their RTWs I hopped back & forward utilizing GVA, BSL, ZRH directly to the UK and also travelled from Bern via MUC or VIE. BSL was convenient IF you hired a car, GVA and ZRH were easy, direct from the airport stations to the centre of Bern. Bern itself required taxi or shuttle bus. ZRH was easily the best route from the UK as it was a much shorter journey than from GVA and also OK with car hire. All drive routes were motorway and quick.