Yep,
We've stayed there and the Abbey Wood CC site.
As Brian says, the bus into central Lonon is right outside the site. As with all CC sites we have stayed at it was well kept and had great staff.
Out of the two though we liked Abbey Wood best.
Why?
The pitches at Abbey Wood are set in a less formal layout amongst mature trees. Crystal Palace pitches are set out in quite regimented rows.
Whilst the bus for London at CP is on the doorstep, the ride can take up to an hour. The train station for CP is a fair walk from the site. But at AW the train station is closer, and it is then less than 30 mins into town. Go after I think 9:30 and you can get a low cost one day travelcard that covers the tube as well.
AW is also close to Grenwich if you want to do the Maritime Museum or ride the Docklands Light Railway.
On the flip side though, there were a couple of nice restaurants within walking distance of the CP site. Not so for Abbey Wood.
Tony