Minor Temp problems 850R Help?

I had a minor problem in that the lights flash for around 15 seconds ran a Volvo tester on it showed an abs sensor fault but nothing on climate control. My car ALWAYS had the temp gauge at around 4.00pm nicely under quarter past the hour so to speak. I replaced the thermostat and the Temp sensor no difference except...It seems to get to temperature very quickly now and settles at 10 past..which just looks a little high..The fans cut in the Air Con works...it just LOOKS a little high could it be the wrong sensor...
As an aside I had it listed on Ebay recently..ran short of money that kind of thing....1st my Son announced that he needed to borrow it.. removed it, then My Wife needed to collect a Dinghy from Brighton, removed it again and finally last week with 28 minutes to go...( it hadn't reached its reserve ) Ebay removed it as I had said that if you want to use Paypal then you'd have to pay the fees...They then automatically listed it again!
Then I get some Herbert messaging me..Chris actually saying its been listed 4 times now it must be a right duffer!!!
I think its trying to tell me something don't you??

Don't sell. If you've changed the thermostat then it might behave differently when building temp. My pre me7 v70r was a different car when I changed the temp sensor & thermostat. Better on fuel.
It's a lovely car!
Keep an eye on your fluids as per the rules & it will be fine.

The needle on all my volvos has always sat at the 3 'o' clock position (or just slightly higher), 4 o clock sounds a little low?

Yeah, 3 o'clock on ours too, It sounds like your previous thermostat had given up, so the engine always ran cool, now you've replaced it, it's getting up to temperature in the time it should. As long as it's not going higher, and as you say the fan kicks in, there shouldn't be a problem.

Changed the stat on ours and immediately made a vast difference, they should sit a touch higher than 3 o'clock