Got Hankook Optimas on 15" rims. Done 14k from new and have 4mm across treads left (including depth indicators. I drive like a Doris with 80% town driving. Is that what I should expect from a front set of tyres?

That doesn't sound too bad. I only got about 13000 out of the original Bridgestones on SWMBO's.

I have the 1.9 which has a lot more weight over the front, and I would get about that much... 10k spent on the rear first, but they would hardly wear at all, and then 10k on the fronts which would gave them down to about 4mm. Also I had to have the tracking realigned as I was being premature wear on the front tyres. But by swapping 2 at a time and putting the rears on the front you get double the mileage from a pair, at least it feels that way. 20k in my instance, maybe 30k in yours?

Yeah that might be about right. I neglected to rotate my wheels, however I did swap them for winter wheels for about six months every year.

 

The rears were on all the time and they got to about 36000 and wore down to between 2 and 3mm across the surfaces.