As a silver member traveling in Euro Traveler LGW-AMS, I got away with checking in about 39kg; the limit was 23kg of course. I was prepared to pay the excess, but the check-in agent barely said a word and did not ever mention 'excess' at any time.

But rather than not showing up with almost twice the allowance since then, I di take that experience as an outlier. A good one though. Go Gatwick!

In general, however, BA has always been good to me when checking in a few extra kilograms. Unless you are completely outlandish and have a ridiculous amount of luggage, they seem flexible to all passengers, including those in economy without status. Others may have different experience though.

Reminds me... last time dropping off my bags at AMS, a man had three massive suitcases for an itinerary with a 23kg limit. Two of the suitcases weighed above the 32kg health and safety limit, and he seemed to have difficulty understanding what the problem was and why he was being required to purchase extra luggage and/or dump two of the bags. In instances like that, I feel, BA stops being generous and starts tightening the belt, as they should. Poor guy though... he genuinly seemed distraught.