Rear side window demister is deleted on mini-facelift (which you're unlucky not to be with a '98) which is where they got the space to stick the TC button up on the row, i believe. If The Boy says it's easy to move, I guess the connector is the same and there's enough wire to move it, so you'll have to buy a mini-facelift TC button and choose a feature to delete to make way for it!
Personally I'd get a TomTom 
Whilst the CARiN is old, slow, bit clunky, I'd still use it over TomTom and other portable units any day of the week. Reliability and accuracy. With an added benefit of convenience, and no telltale rings on the windscreen to attract scrotes...
Before the TT fanboys pipe up how wonderfly accurate and reliable TT (and similar units) is, trust me, not a patch on the 15yr old CARiN

. This is why one of my TT units is somewhere on the Birmingham/Aston Expressway. And deservedly so, useless heap of junk.
TT has its place, and is very useful (I have replaced the one I threw out of the window), but if there is an option for a factory fit one, I'd chose that every time.