I am worried my 4sp gearbox is beginning to show its age. (180k)
When accelerating very hard (foot to floor) , or indeed very gently (grandpa mode), there is a wobble that is becoming very pronounced.
If you accelerate normally, no issue...

Your thoughts?...

Wobble? And you instantly blame the gearbox?
Sounds more like a drive shaft problem, or tyre balance.

Have checked tyre pressure and balance today...all is now good with them.
Re drive shafts, what do you suggest to check / test?

One (meaning yourself) jacks up one front wheel, puts car in neutral, and turns the wheel by hand. If one finds a definite hard-to-turn spot, or hears a noise, one needs to look closer. Look for split CV joint boots, and look for play in the joints at the wheel and near the gearbox by trying to wriggle the shaft up and down as well as back and forth at the joints.

I hope you don't find this:

http://2.bp.blogspot.com/-SLJbA6wjJFU/UM19h4ZKTlI/AAAAAAAAASA/d_TMTWKH_SY/s400/cvboot_torn.jpg