In case anyone is wondering what radiator re-coring costs, just got a quote of £190-something + VAT from
H&L radiators in Ludlow
, Sheepshire, to which the answer was "yes please". Should be done by the end of the week.
I did use that Wynn's flushing stuff on the rest of it, no idea whether it's helped. I joined the front pipes with a bit of plastic 32 mm waste pipe from B&Q* and watched the temp gauge while doing the required 10 min + running with the stuff in, with th expansion cap off. Interestingly, with the heater and blower on, revving to 3000 rpm or so brought the temprature down as it pushed water through the heater (and made the air coming out noticeably hotter). I disconnected all the pipes, took th eengine drain plug out and hosed through everything. The flushing stuff came out a pale pink colour. Did have one odd thing - the expansion tank refused to empty while I was trying to flush through the block. I disconnected the hose from that at the head and blew water back the other way, back into the tank. Ran through fine after that.
The new drive looks lke it will be finished today. Hopefully no more need to crawl under it in the gutter - I can fill the block with coolant/antifreeze and get it the 20 metres or so on to ramps in the garage before the thermostat opens up and dumps it all on the floor (rear hoses are off). Maybe join the outlets to the radiator with the old hose to be on the safe side, with the heater on again.
Anyway, hope that's it for a bit. This year or so it's had a new speedo cable, clutch/release bearing, brakes overhauled, new clutch and brake master cylinder, and new timing belt/tension bearing, in addition to the re-cored radiator and new coolant hoses all round it's about to get.
*Fits very nicely into the radiator hose - a bit of this pipe with a washer machine waste nozzle on it to take the hose pipe would be a great way to flush out the long pipes from the top of the floppy hoses without spraying water everywhere.