Welcome to BF! Great looking bike.
I used to live near Swinley Forest - just off Devenish Road in Sunningdale. (That's less than a mile away, I think).
We took a walk once to one of the sites of the hill forts in Bracknell Forest - must be close to where you mountain bike?
http://www.bracknell-forest.gov.uk/leis-caesars-camp#
I never did off-road riding but used to ride my road bike over to Windsor Great Park and roam around the paths there. My kids were younger then so we did lots more hiking/walking around the Great Park than biking.