if they make the offset to fit a TA22 and you keep the overall diameter of the tyres the same it shoule be alright using 7" wheels. I've seen it on many 22's with no problems.
I'm using 15x7" and I have scraping (when bottom out) and rubbing at rear wheel arch on full lock - This is due entirely to the incorrect offset of my wheels.
Having a 16" diammeter ain't an issue, as long as you reduce the profile enough to suit.
You might want to check the track you have now compared to stock at the front due to the RA40 brakes (if its a total strut change). A wider track might mean you'll need a deeper offset wheel on the front than normal to fit the wheels under stock guards.
Cheers.
ps. personally I don't think 16" superlights will suit the TA22 if in the silver color.