How much are they knocking the R out for - assuming it's pre-reg'd? I bet it's not for as good a deal as you got MH! 
The salesman I talked to (as my regular one is on Holiday until Monday) about adding an extended warranty to my R (in case it ends up here and registered before Friday) said they want full price for the R or very close to it. They have supposedly had lots of offers, but not close enough.
I did pretty well out of my offer (moreso the p/x price - I would be looking at £700 less than I got for it if my salesman had realised when the R would actually turn up. I doubt i'll be troubling my salesman for the Polo GTI at broker prices, will probably be a resounding "sorry!" to get anywhere close. Pity the 2 year extension has gone up £55 with the latest price rise.