I’d say turn up anywhere you like on whatever bike you like
When I moved to the NF I was riding round on a bullit with a dual crown fork
I don’t know of anywhere within the NF that a 150mm enduro bike will be “necessary”, or that will scare the shit out of you (though I don’t know your riding) but you can have some fun in amongst the flattish xc
There’s also moors valley park – the blue trail there is quite good fun if you’re going fast and counts as singletrack in my book. There’s also a “freeride” area close by at watchmoor, though I don’t know what state it’s in
Other way, Lordswood and the pump track’n’shit at southampton sports centre. I think Avon Tyrell also has a pump track and maybe some trails, though I’ve never made it to a bigbikebash to see for myself 😳