Well now .... I went to the garage and whilst the mechanic was listening to the noise from the N/S drive shaft, he agreed that the temp was incorrect. It was either the thermostat or the sender. More likely the sender.
When i pointed out the slow warm up and low heater output he changed to more likely the thermostat...........
When it goes in to have the N/S drive shaft noise sorted AGAIN ( they changed the O/S DS bearing last week despite the noise coming from the N/S!) they will sort the temp out..... I hope.
I'll let you know.
Thank goodness for a years warrenty! Otherwise I would have had to have covered a duff battery, seized rear wiper motor and rattling boot lid so far.........
Thimk I might join the 'Why I hate my GTI' thread!