Thanks for all your input on a suitable headset for my Freddie Grubb. The overall favourite from your responses was a Tange Levin or Passage as it now seems to be called, with Shimano 105 getting an honourable mention along with Campag Pista. Went for the Tange and it works fine. Its very low as we needed a spacer under the locknut! Not the prettiest or smoothset of headset but it does the job.
Stewart