I ran a pair on a dual disc 26" bike a while back. Not the best with standard pads and discs, but an upgrade to jitsie / trialtech pads and hope rotors isn't too pricey and made them work really well. I think they have a decent lever feel.
Trails or Downhill?
These might be a little out the way: http://www.7stanesmountainbiking.com/
Bit closer to Aberdeen: http://www.glenlivetestate.co.uk/
There are lots of non trail centre places too but the weather is getting worse up in the Highlands that you might be a little limited.
There are also some trails near Stirling University in the woods by Dumyat/Blairlogie (https://www.google.co.uk/maps/place/56%C2%B009'27.9%22N+3%C2%B052'33.2%22Wfirstname.lastname@example.org,-3.8918322,3055m/data=!3m1!1e3!4m2!3m1!1s0x0:0x0 park here: https://www.google.co.uk/maps/place/56%C2%B008'52.4%22N+3%C2%B054'16.3%22Wemail@example.com,-3.9067087,741m/data=!3m2!1e3!4b1!4m2!3m1!1s0x0:0x0). Also Carron Valley trail centre near Falkirk but it's pretty basic.
Hoepfully Ross will be able to post some stuff closer to the Glasgow area.