Blue is very easy to find
The red is ok but you need to keep an eye out as some of the direction posts can easily be missed as there are lots of off piste trails which have been created.
I tend to do the start the red from the trail centre but the do the “Adit” additional loop which makes it about 10 miles long. You come to a junction after about 4 miles that gives you the choice of taking the extra loop or the doing the shorter one
Watch out for boar – I have had ones pass across in front of me on my last to visits