I can understand your frustration; indeed the WLAC website
West London Aero Club - Bar and Catering states:
The bar offers a warm welcome to all members and visitors. Breakfast is served from 8am until noon and is worth flying in for. In good weather we can offer the delight of eating alfresco on the lawn in the front of the clubhouse, stay long enough and you will experience one of the most beautiful sunsets in the country.
To me, this is somewhat ambiguous - 'visitors' does seem to imply that
anyone 'visiting' is welcome whether arriving by land, sea or sky. OK, perhaps forget sea.
A polite note to WLAC requesting clarification would seem appropriate. Mention that you were rather disappointed to have been refused admission, particularly since you have been a regular flying visitor for quite some time.
Equally, one can well imagine that uncontrolled numbers of visitors would seriously annoy Club members and that, of course, should be respected.
I once planned to fly to WW to meet a friend for lunch (she of
Pink Headset fame!) who was driving from London. The weather was horrible, so I drove instead. When I arrived, I signed in and went straight to the bar manager and said "I was intending to fly in to meet a friend who's coming here for lunch, but I've had to drive due to the weather - will it still be OK for us to have lunch?". No problem. And the fish and chips were great!!
But WLAC could usefully clarify the club house admission rules on their website, I do agree.
I've been going to WLAC for nearly 40 years - I plan to go there on the 40th anniversary of my first ever visit as a ULAS student later this year. It's always been a wonderful place!