well, I have now plotted routes on the OSMap GPStraining free online planner
Pulled in GPX i have found for various places - Devon, Dartmoor, Exmoor, Forest of dean, Scotland , Isle of Wight , Sidmouth and various routes around my home
modified routes, changed direction , created from scratch , that all works well and they load into various online apps OK too
Been on a few rides with the ROC and still working on the finer details - BUT it seems to work well so far
Will be tested in anger when touring the Forest of Dean in a few weeks , weather permitting
I'm now trying out the Twonav LAND application , a bit like basecamp - but as i have paid for all the 1:25K oS maps , I can use on LAND as well so giving that a go
Thanks again to everyone for advice and support