OK, ta for the info. Sounds like it might be possible to link it together from the newer routes then (if the flow of traffic allows). I think the old route started off by climbing up a fire road that ran to the south/south west of the old (nice) cafe, then dropped down some gently descending 'flowy' singletrack – but kept to the west side of the A470 for some way. Can't remember how & where route crossed A470, but seem to think the main climb was on east side of road.
I remember some of the names mentioned on the Cyflym Coch route – the distance also sounds about right. Just wanted to check, cos never know how the FC's tree-felling/re-landscaping can affect things. (& last time we were there was in 2002!)