Thank you all for your replies.
In the end I used E.B.Spares,The Alfa Romeo Parts centre, in Westbury Wiltshire.
They provided excellent service and have my recommendation.
The parts were Valeo and total price, including VAT and next day delivery,was £212.08.
At the same time the thermostat was replaced (temperature gauge not moving,heater lukewarm) which cost £39.09 (QH)from Rapid Car Parts.Temperature fine now.
The clutch pedal is still not quite right,it has at times too much free play and needs pumping a few times and this seems to clear it. Perhaps bleeding or possibly the master cylinder.I shall check it out.
Thanks again for a very helpful forum