The venue is Abbey Recreation Ground off Morden Road, Merton. I’ve attached details from the council and also a map of the location.
http://www.merton.gov.uk/environment/openspaces/parks/parks_in_the_morden_area/abbeyrec.htm#location
https://www.google.co.uk/maps/@51.412099,-0.193589,17z
There are toilets on site but no refreshments - Old Ruts will bring drinks and snacks for the players but parents may wish to bring their own coffee!