I would like to keep the wheels, they do make the car look great although as it turns out not to practical if you want to carry passengers.
Well, please do get the rear springs and spring seats looked at, either by yourself or somone who knows the A2. I've seen countless A2s where the spring seats have totally pulverised to nothing. From your profile, I see your A2 has done in excess of 151,000 miles. If the spring seats on your car have never been renewed, then chances are they'll have vanished long ago. Small breakages of the springs are usually spotted by MOT testers, but they can't spot missing spring seats because they wouldn't know the part was even supposed to be there.
There's no reason why you can't keep your TT wheels and have a perfectly functional A2. The tyre size and wheel geometry you've got is used by loads of people here. Almost everyone who uses the 7-spoke TT wheels (shown in the photo below) has 205/50/R16 tyres fitted. These wheels have exactly the same geometry as the 5-spoke TT wheels that you have fitted; they're 16", 7J, ET31. You can, however, fit 205/45/R16 instead if you want to decrease the size of the tyre's wall.
Plenty of people who use the same wheel/tyre combination load their cars with passengers and other heavy stuff without issue. My own wheels are admittedly ET35, but that's not a massive difference and I've never come close to scrubbing the rear arches. Believe me, I put some weight in the back of my A2 from time to time! In the photos you've posted, is there a lot of weight in the back of the car or is that the car's natural stance?
You're within a short distance of WOM Automotive, who know the A2 inside out and will be able to assess your rear suspension in a flash. Plenty of club members only wish they lived closer to them. I don't know how handy you are with spanners and such, so forgive me if you're perfectly capable of assessing these things yourself.
By the way, I posted some info/photos on your thread about wanting a Concert stereo. I hope it's helpful.
Cheers,
Tom