Thanks for all the replies so far,
Does not sound as if it is a major job to get it changed, I'm sure on occasion instrument clusters go faulty post delivery and have to be replaced so it can't be that difficult. Should only be in the shop for a day, I presume all the connectors are the same in the back of the cluster, will just maybe need reprogramming somewhere to let it know it's now colour, plus the keys thing mentioned above.
The dealer was being a bit evasive saying it could not be done but I now think that's them seeing any profit they made being eroded. I can't imagine the correct cluster would be cheap but at the end of the day its their error and they need to sort it out between themselves and VW. I'm also prepared to give them the £135.00 back.
I have taken the car away as I had already swapped insurance, its registered with a private plate and the trade in was on its last legs so I was put in a bit of a difficult position if I rejected it there an then; me and the wife may have been walking home.
On the positive side the car looks and drives fantastic (10 miles so far

), it's such a shame that this one problem has taken the shine off it.
I've been doing some WWW digging to try and find an exploded diagram of the dash but have only found a MK6 LHD one so far and that looks a fairly straightforward swap out.
Any other help, suggestions or part number(s) much appreciated.