A thank you...
Thanks for all of the info I've gleamed from this thread. I've just replaced my stat as the gauge was only reading in the area of 55 degs. So after some struggling (yes it may be a 20 minute job, if all the hose clips have been replaced previously!!) it was replaced, all new hose clips fitted including the air intake ones (and running 2" wide tape around a split in the flexy hose after warming it all up) and then a mixed driving test drive..... Result PERFECT!!
Sat on the drive afterwards with the laptop hooked up and she was running at about 90.1, then steadily went up to 99.0 as the fan kicked in.
I'm very happy with that, so a huge thank you to all on here!