Hi John, - this is my first ever post so if I get things wrong, forgive me.
First a quick background then I'll get to the point,
I'm in my seventies, and last year I bought my first bike since I was a teenager - a second hand - 'Charge Duster 11' - 2012.
which as the name implies has a Shimano Alfine 11 IGH.
Hence ever since I have taken to looking on various forums to see what's to learn about these new fangled gears,
and that's how I came across your question - 'Alfine 8 for commute in East Anglia'.
You began with 'I hope it's not a stupid question' just as I must start with 'I hope it's not a stupid answer' but here goes:-
The first thing I noticed with the Duster was a complete waste of time gears 1 - 5 were here in Leicestershire,
and we're not as flat as you're in East Anglia
Even with the few 'inclines I 'negotiated' on my exercise rides I rarely dropped below 6th.gear. (and that's at my age)
I soon realised I'd got myself a mountain bike to do a road bike job, so I decided to change the gear ratios, I 'upped' the front cog from 32t to 36t.
and the rear down from 20t to 18t. This upped the overall gear ratio by 25%, even so, I still don't use 1 + 2 and occasionally feel I need a higher gear going downhill.
Two reasons I didn't go for even higher ratios :- 1) I didn't want to fork out for a larger chain guard that was required if I was to fit an even larger chain wheel,
and 2) If I was able to go any quicker downhill, I'd probably kill myself!
TO MY POINT:-
Unless you do something drastic, like fitting cogs to give a 2 : 2.5 ratio (18/45), I think you will soon get very frustrated with an Alfine 8 on East Anglian roads.
I realise my comments are based on my experience on the '11' but bare in mind, (if you weren't already) that bottom gear in the '8' is the same as the '11' -
= 0.527 and that up to gear 5 there's not much difference - (gear 5 on the '8' = 1.00 /on the '11' = .995) - it's just that my top gear, - now at 112 gear inch,
would be 25% higher than say a 'standard' 8 on a 28" wheel, at 90 gear inch.
However, if you go ahead with a new purchase, bare in mind, the warranty of the gears may come into question if you go as far as I'm suggesting.
Finally,now that I feel that I've got the Duster to my liking, I think it's a great bike, and love the gear changes while at a standstill, and happy to recommend the 'Alfines',
(with the right cogs).
I hope that doesn't read too 'stupid, - I've gone on a bit for my first, I hope it's of some help/ food for thought.
Regards, momo