My problem seems to have been fixed thanks to the lovely American lady I spoke to at Apple Support - hoorah!!
I had already reset my iphone 4 to factory settings, but I then reset it from the iphone back up - didn't really think about it - just assumed as it wasn't a new iphone, I should use my back up to get it sorted!! Apple lady told me I should do the factory settings again, but this time set it up as a new iphone and lo and behold - one happy iphone - no more telephone problems and no more wi-fi issues. The way she explained it was that if you simply re insert your old software, you probably re insert the glitches apparently already there - kind of obvious I guess!! Anyway - thanks Apple - my iPhone is alive and kicking properly now - all I need to sort out now is the glitch with the newest version of iTunes (although not affecting the new iPad), which is not allowing my iPhone to see any of the 96 playlists I have on my accunt/icloud (I've currently turned off itune match on the iphone and synced directly to my account like the olden days!) - I've baffled the guys at Apple who are currently investigating this one for me - I like to give them a challenge every now and then!! Hope this factory setting info helps someone!