In reply to Fiona Reid:
> If Tiso isn't an option then perhaps Craigdon - not sure if the Edinburgh one still does ski kit since it downsized?
Last time I was in the Edinburgh Craigdon - early this year, so still during the ski season - it was pretty much all ski stuff. I suppose it's possible that they change the stock around according to the seasons, or adjust the proportions, but given that they had what seemed to be a dedicated ski workshop in the back corner of the basement they now occupy underneath Sainsbury's, I'd be surprised if they couldn't do the job required. (They were certainly prepared to give my skis an edge & wax before I next went out.)
I replaced the heels on my own 20+ year old resort skiing boots last year, after they (the rubber heels) had perished and fallen off mid-holiday (eek). They came with the necessary fitting screws and the job was pretty straightforward. As mentioned above, given that the holes the screws go in to are in a plastic moulding, it's advisable to take it easy with the torque you apply through the screwdriver. If you're not confident that you have the necessary "feel" for that kind of thing then best get someone else to do it. At least that way you can blame them if your otherwise OK boots end up unusable...