In terms of getting there, the nearest train station is Barnes and it’s about a 15 minute walk from there north up Rocks Lane / A306. Alternatively, you can get off at Barnes station and jump on either the 33 or 72 Bus to the “Red Lion” (post-drinks) bus stop. The below link outlines the route, although you can just follow the signs for the “London Wetland Centre” which is right next door:
There are parking facilities on site, however I was warned a few weeks ago by the ground that parking is severely limited (20% of normal capacity) due to ongoing construction at the site. If you wanted to play it safe, I would suggest the above train-walk/bus combo.
Once you arrive, if you ask at reception there will be an away dressing room allocated for OMT’s. Post-match tea will be served in the Barnes RFC clubhouse afterwards.