First games are planned for 19:05, with coaches briefing 18:45. As a result, we’d recommend arriving at the Rock for about 18:30 to warm up etc. there will be footballers (booo!) on the pitch til 19:00 so we will need to be clever sharing in goal and dead ball areas but we’ll manage.
Can you tell your parents that taking public transport would be appreciated as there isn’t much parking space at the Rock? Trains to Barnes station and a 5 min walk, or there is the 337 bus that runs between Wandsworth and Richmond - you want the stop called Queens Rise and it stops outside the Rock.
Suggest taking 18:14pm train from Chiswisk to Barnes, to arrive at 18:30. Trains run every 15min.