Thinking about ditching the road bike,had too many near misses of late. Can take an alternate route which involves a bit of bridleway, canal towpath. Nowt too rough, are they durable enough?

Steve of Square Wheels swears by his (on a Swift). It gets used on much rougher stuff than towpaths 🙂

Yep. Lots of people I know using them off road in all conditions with no problems.

I'd have thought its the sealing that's the issue rather then terrain (bar lots of steep climbs).

Mrs F has had an Alfine on her Inbred for a little over three years, and has ridden it pretty much daily since, including some pretty rough stuff and in all weathers. I took the hub into the LBS for a speculative service last year, they disassembled it, regreased etc, but said it actually didn't need any attention at all – no ingress of anything – so I guess the sealing is pretty good.

The Hub at Glentress use Alfine equipped Genesis iO ID as hire bikes so that says something about the suitability for off road use.

what sort of gear spread do you get with these things? Is it like running 1 x 9?

Pretty much like running an 11-34 8 speed cassette gear spread wise.

tempting. I had a mech destroy the spokes on the drive side of a wheel a couple of weeks ago, some sort of alternative is very appealing (cue responses about correct mech adjustment…)

almost 200 miles mostly off-road and can't fault it, it even leaves the ground!

Alfine 11spd on the way but proper money £375 ish plus shifter. That will be XT quality. The 8spd Deore quality current one is great though and more than a match for what you want to do with it.