Distance versus climbing

Had another good run today in Port hills. The link here gives a little bit of the route just to give a taster of what these hills are like. If you can't be bothered to follow link then terrain is a bit of a mix of running some of the moors in West Yorkshire, some of the route of Seven Sister's marathon etc etc. Thus, there is quite a climb to get on to summit road then all the paths round there are fairly hilly but with shorter sharper sections.

This photo gives an of idea of the sort of terrain along the tops (actually the track to the left is the easier track that comes up from where I started to the same point at summit). Summit Rd is the road running left to right and is where all paths from base of hills come out.

Photo borrowed from this guy (who I hope doesn't mind!)

For the Surrey boys, this terrain is much harder than any of our terrain on our Sunday runs but for Jock, this is more similar to the hills running behind your house (only the climbs are possibly a bit longer). For the Coventry boys and Bham contingent; forget about it! The only terrain anything like this would be Malvern Hills but with smaller and more rock strewn paths.

Only did about 10km in total in about 1:10hrs but with about 330m (1000ft) climbing in first 2.4 km on small track with lots of twists and turns plus rocks, and a further couple of climbs that took ascent in total to about 450m (about 1400ft) it was pretty tough for me.

Anyway, pretty tired after hour or so and got to thinking what a hilly run like this was equivalent to on the flat. Obviously hour on the flat would be easier but would definitely have run faster on flat. Fell runners reckon that running on hard fells is equivalent to running twice that distance on roads. This run wasn't 'hard fells' but certainly would have fallen into a fell running event category if the route was ever raced (and in UK of course!).

So, what do people think? Is an hour or so on hard and hilly terrain equal to 2hrs on roads/flattish terrain (about 14-15miles/22-24km) or impossible to tell? Partially wondering as not sure that I could run strongly over 2hrs even on road at moment but could plod my way round 1:30 on hilly terrain without killing myself