Bought a Radiator from Ebay at 1am Wednesday morning, turned up this morning when the delivery driver turned up at 8am, now that's what I call service. Great price too, at £93 delivered for a new unit, it was a steal!
Set about replacing it at 12 and job done by 3pm at a very leisurly pace.
There was sludge in the bottom of the expansion tank and obviously some came out the bottom of the Rad. I back flushed the engine block and very little came out.
It definatly looks like some one has used rad weld in some form before as it has all the usual signs and I guess these metalic looking flakes are aluminium flakes used in the rad weld. I just hope that the rad weld was there to fix a leak in the radiator and not the cylinder head or heater matrix
I purchased a slightly more expensive Antifreeze than I would have normally done and went for the Green stuff and at £18 for 5 litres, for this I was expecting gold flakes in there, however when I started to dilute it it was a shade of Blue.....Very weird! I spoke to comma customer service that assured me this was the right stuff, I'm not so sure and feel a little cheated as it's not coloured green (see the pic and make your own mind up).
I held off the water pump as for one I didn't have enough time to buy one and fit it and if the water pump did start to go, I could replace it really easily.
The upshot of all of this is the problem seems to be fixed now.