Well wasnt today a fun day lol
Got it all done in the end.
But what a caper!!

Eventually got the viscous undone by usung the open end of a 10mm spanner o one of the loosened pulley bolts and bracing that across the other one. Acted like the Sealey tool mentioned above.The i braced that a against a 9mm spanner held against the engine and my hand.
Then after bending said bolt i was resting against, it eventually came undone.
To top it all off then,
Was Fitting the new water pump, screwing in the bolt a bit at a time around the four of them.
None of them were anywhere near tight,
and then what do you know,
1 sheared off! right there and then under hardly any pressure.
Took the pump off again, there was enough thread hanging out of the block for me to be able to grab it with some pliers and undo it.
Anyway, had to walk to town to get new bolts from the hardware shop.
Fitted.
Tighten, replaced everything.
And now the tensioner looks like its a bit weak.
The tensioner pulley is bouncing a millimeter or 2 at idle. Still hold the belt and doesnt slip, but will need doing eventually.
That should be pretty easy though, having done this.
New coolant in.
job done.
NEVER AGAIN!! lol
I dont think my knuckles could take it