I've had my S-Type for a little over six months and still loving it. This forum has been really useful and I've now got it in top condition after reading up on them and fixing all the should we say "common" problems these cars can get (which mine had most of! 1st gear lurch, water in boot, door handle not working etc)
Now I have a new problem that I am hoping will also be as easy to diagnose, since I am not up on car mechanics myself. I have noticed that between 50-70mph the steering wheel gets a but of vibration coming from it. At first I thought it was a balance weight or something so got them checked out, but after that didn't cure it I got the wheels rotated and it also made no difference. The car tracks straight and true when you take your hands off the wheel, even in the 'vibration zone', but I have also noticed that sometimes on well-worn roads or occasionally when changing lanes that it 'tramlines' a bit, where other cars I drive on the same bit of road don't.
I am currently over in Sweden for a few months and repair costs over here are high, so if I can safely live with it for a bit I will until I get back to the UK. Otherwise if I can get some hinters I'll take the hit and get it seen to here.
Also check that the front tracking is set correctly. On a smooth road a car will track 'fine' even if the toe setting is a bit out, but it will be more sensitive to road imperfections. A simple check is to see if there is wear on either both inner or outer edges of the front tyres. If the toe is out, this wear pattern should match. You should be able to feel it more than see it, as the front edge of the blocks get chewed up and are almost sharp! Put the steering on full lock and run your hand back over the tread against the direction of rotation and see if you can feel a difference between the inner and outer edge. If the toe has been out for a while, one edge will feel rough and the other more-or-less OK.
Thanks for the hints. The car still has the same tyres on it was bought with just before Christmas and I'm sure I've not hit any big bumps or holes at speed to do any damage. Also had the tryes rotated and the balances checked, so probably looking like bushes or tracking related.... I'll get it in for someone more expert than me to have a look!