If you are after a 'perfect' TT6 with colour preferences then you are probably only going to see joy by importing one from Japan as you have 10 times as many Supras there to choose from and rust is less of an inconvenience than with UK resident cars.
I was looking at the latest Japan listings yesterday and the prices have reached Y2mn minimum now for usual mileage RZ's up to Y5mn, so perfection now costs minimum around £27k+ landed taxes paid in the UK for a stock Supra. I think this will soon be reflected in the prices available from the usual importers who are actually offering very few TT6 Supras these days relative to other imports. Maybe the market is starting to baulk at the import prices but if it is, I'd venture it'll be a temporary gasp to the onwards and upwards for in particular, stock Supra prices.
There are very few stock TT6's being offered for sale at the moment, so again importing is a more secure route to getting hold of one in the near term. You may be able to maximise a part ex value for yours with one of the usual importers as well. I'd recommend go chat with the guys at JM, DCE Europe and HJA. DCE have a teaser ad in PH saying import this car for £19,985 but when you talk to them they say allow around £30k. So you are looking at a big money upgrade to fulfil your search for perfection.