Well, I have done the deed and ordered an A5 this afternoon via our leasing company

A5 2.0TDI 170 Sport
Deep Sea Blue
Sat Nav
Advanced Parking System
Heated Seats
Auto Hill Start
Auto Dimming Mirror (inc auto wipers/headlights)
Bluetooth Low
Cruise Control

Cost : £31600

The only option i debated was the 'comfort access key' but decided to miss it in favour of the advanced parking.

Audi are offering a free upgrade from 2.0TDi to the Sport model and also including bluetooth and cruise control. This gave a reduced list price, reduced lease rate and lower tax bill so meant i could add a few extra options.
Also Audi have a price increase coming in on 23rd Feb so hopefully I have avoided that (though not sure yet)
Another bonus may be that Audi website is now saying the CO2 emissions are 139 versus the 140 it said in Jan so thats 1% off my tax bill

Only down side is that my current lexus Is220d lease doesn't expire until 1st week of May so thats the earliest I can have the A5.