right you can all ignore this as I've fixed the problem lol
I played about with changing gears. it seems I've not been putting my foot firmly enough on the brake when I shift. as soon as I do this the gear selector slides straight in with no resistance at all I thin my old car doesn't need the brake to be depressed that much but this one does... i'm thinking something is engaged to free the gears to move... and I just needed to be a bit firmer
I had exactly the same shake through the steering wheel between 70 and 80. Went and had the wheels balanced today. £12 for all four wheels to be balanced (just that - no new tyres purchased) and that's sorted it.
If you have severe uneven wear (like it sounds you have) you should get an alignment done.
The guy in the pic on the right is Tony, the head poncho. He really knows his stuff
Finally (if I've read your post correctly) you don't have your locking key nut.... any tyre place worth their weight will be able to chisel them off and you can either replace with normal lug nuts or buy a new lock kit. I got mine off myself... hit it with a bolster, knock it round with a punch