I used the Club in August - 2 nights in a mini-suite. Very comfortable, and I enjoyed the brekkie. All in all, a good weekend attending a wedding and visiting old friends!
Pontius, I used Vinci parking underneath Park Lane, just north of Hyde Park Corner. It is possible to get a RAF Club discount there, but only upon presentation of an accommodation bill from the Club. Consequently, if one uses Vinci's online booking (to ensure a parking space) there is no discount - I confimed that with them. Online means book and pay together - c'est la vie! So, if you want the discount, you have to take a chance there is a space available when you turn up, and pay in arrears. Nevertheless, the convenience of the parking lot suited my needs.