
I went on down to Venturesport today, to see if they had any crampons in stock (last time I went in, they hadn't). Luckily I'd managed to pursuade my parents to drop my boots off this morning, so I could actually wear the boots at the time and get the crampons fitted properly.
My size 45 Scarpa SLs fitted perfectly on the very last hole on the crampon bar (I chose the Grivel G10). This suggests to me that Grivel's claim that the crampons will fit up to size 46 is not true, because if my boots were literally three millimetres longer, they wouldn't have fitted. So please bear in mind that if your boots are bigger than size 45, you may need to find the long extension bar!
Because I have such big feet, the assistant warned me to be careful when walking on ground with sparse snow cover. Stomping down on a rock too hard could easily break the extension bar, which is extended to its maximum length. Unfortunately Venturesport don't sell bars which are compatible with the G10--I haven't been able to find anywhere that does, actually--but the guy was confident that a place in Ambleside stocked them. Since I'll be doing most of my winter walking a stone's throw from Ambleside, I don't think it'll be a problem.
I was very impressed with the quality of service. The assistant spent fifteen or twenty minutes going over the important points of crampon use (I'm a winter newbie) and showing me the best way of sharpening, caring for and storing the crampons. If you live near Norwich, I thoroughly recommend Venturesport! Plus the whole lot (including Grivel crampon bag) came to only £80 with my BMC discount, which is cheaper than it would have been from Cotswold.
Now all I have to worry about it the weather over the New Year!