Hi, to update. I now have air conditioning....wahoooo and the system doesn't appear to be loosing any more water as previous.
....with the help from Laz and the link above (thank you)
I replaced the heater control valve, the radiator (see pic of the old one) (after 4 attempts at getting one delivered)..the first one was the none oil cooled - mine is oil cooled, the second was also damaged with the lugs and third was another issue in that the oil outlet connector back to the auto box wouldn't connect up...too small. I even tried the old one to restore some sanity to my by now frazzled brain and it was fine to fit. The rad dealer was initially having none of it though. I insisted they sent another so i could get back on it first thing the following morning. It duly arrived at 8am but was also damaged again in transit as one the lugs was partly snapped off.....Grrrr .. Despite this further set back i did manage to get it to fit with just enough lug remaining....just as well as I couldn't wait any longer......
The top hose was also replaced with a genuine as this was cracked on what seems like a baco-lite connector and was a leak source...see pic. I also took the opportunity to replace the cracked serpentine belt...this was a little challenge because the well known motor factor couldn't decide which would fit so gave me a couple to try....but asked me to pay for both! They were both short by 4 or more inches so i took my belt off and took it with me to compare... they didn't have any remotely near so went to Jag dealer in Norwich. Downside.... whilst paying twice what the factors were after ...upside it measured up and fitted perfectly at Jag dealer....result.
I also cleared out the in-cab sensor as a precaution as upon inspection this appeared to be chocked with dust etc.
Overall, whilst it went as I had expected (some struggle normal) and with the help from Laz and the link above (thank you) I had also expected that the captive bolts that hold the inner liner and under-pans in place would come off with a little force i was completely floored and took the whole lot off including the bumper. They had to be cut off carefully as they could easily melt the plastic surrounds. I ended up with some plastic repair work to the bumper where the connectors come together and the under-pan. The Inner arch liner wing clips were also replaced (main dealers at £2.50 each) as they were in bits too. I got a full set of SS screws and U clips from E bay. http://www.ebay.co.uk/itm/S-TYPE-JAGUAR-BELLY-PAN-UNDERTRAY-SPIRE-SPEED-CLIPS-STAINLESS-BOLTS-SCREWS-X-25/121492014899?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649. These were a great improvement once applied with some large helpings of spray grease.
Its now back on road and now looking at what else i can sort in my spare time.
Next job....I have a small oil leak at the bottom front of the motor....maybe a sump gasket ?