BD flights are generally quite seasonal as far as prices go.
There are some offers at the moment to go from London-Scotland for GBP25 each way (including taxes etc).
UK domestic fares are generally very cheap if you get in early... and most of the fares are about 90% tax... which you would still have to pay on an award ticket... so I personally don't think they are good value to use points on, unless maybe you are considering a business ticket... but then the longest domestic flight is only about 1:30... so could also be classed as a waste of points.