You know I always turn to you here at Daves when I start to pull my hair out. This one has been getting to me for so long now I just know someone on here will ID it in a second.
Many thanks in advance as usual and I cant wait to say Doh! I thought thats what it was - lol
Looks like a type of Tradescantia. Maybe "Rainbow Hill" ?
One of the girls said possibly Tradescantia but I didnt think it was. That'll teach me for doubting :-)