Andy
Thanks for the suggestions – I've tried Anglia Preceision and River Circle, one said they'd try but couldn't guarantee success. If they failed it would cost me £35 for setting-up costs, the other said it was too small. I hadn't found Qualitech – thanks for the lead, I'll try them. At my age, time is more precious than money and I'd spend some of the latter to save some of the former.
Bernard
Michael
Thanks for the suggestion and detailed instructions – if all else fails, I'll probably give it a try, but as I explained to Andy, my time is now so precious that if some of my children's inheritance can buy me some of the priceless stuff, they encourage me to take that route.
Bernard