I've been and watched London 1st Team, Reserves and Academy at the following grounds:-
Craven Cottage
The Stoop
The Valley, Charlton
Griffin Park, Brentford
Barnet (The Hive)
Bridgend
Henley RUFC
Gillingham
Harlequins RUFC
St. Mary's College, Roehampton

What other grounds have they played on?

Chiswick, Barnet Copthall, Esher RU, Stamford Bridge, Perpignan, Wycombe Wanderers, Leicester?

We played a game at Esher once (Catalan Dragons I think). Also Bridgend Brewery Field.

Did we not once have a on the road game at Coventry? But I remember that Cats game at Esher very well. Was in on a Tue or something

I went to the Bridgend game

I just remembered it was not Coventry we played at, it was Leicester (vs Hull I think).

We played Warrington in Carcassonne in 2002. I also remember we played at Crawley once and at Leyton Orient too.

We played Bradford at Leicester- seem to remember the club organised coaches for season ticket holders

Did we play a cup game at Kingstonians ground?

Hendon FC.

Are we counting friendlies? If so: Wellington College, Crowthorne (against Swinton). Shortest trip I ever made to a game as I lived across the road from the playing fields at the time.

Crystal Palace National sports centre.

We played Widnes at Aberavon, Port Talbot. We also played at Newport. The academy played a number of games at the Military stadium, Aldershot.

I think I recall Reading and was Kingston mentioned. I've been to all those and didn't realise how well I travelled in the past