Nav is a must for me. I'd drop the PP.
Since I ordered I now think its too expensive. I'm thinking if dropping PP, DCC, leather, sunroof and saving £3.5k. My advice would be cut your options back as much as possible. You don't need PP.
Recent events have seriously changed my views.
As said before, the options are pretty much dead money at resale time - your £3500 spent will probably retain about £1000 at most. Is £2500 you'll never see again well spent on those options? All down to personal choice, none of the above are must-haves. What else would you rather be spending that £2500 on, if anything?
PP - you get the visual improvements (brakes) and marginal performance gains you'll only appreciate on a track.
DCC - driven standard ride on a test drive and found it more than adequate?
Leather - boiling hot in the summer, big battery drain in the winter if you like heated seats - the plain leather also takes something away that is integral to the GTI identity inside the car - tartan seats. If looked after with a decent protector, your cloth seats will still look like new after 3 years.
Sunroof - Do you think the inside of the GTI looks claustrophobic or do you think the black headlining looks great? Want a bit of a breeze on your head, then point the vents upwards.