Well, Graham, you are talking of nearly 40 years ago since the last online record! It's amazing how the years slip away, isn't it?
They could well be ex-dir as many are these days. It could cost the best part of 30 quid to do a search on 192.com. Central Library has the Electoral Roll up to 2002, I believe, but it's only indexed by street, not name, as far as I know.
Maurice
EDIT: Actually if you do a search of 192.com via findmypast.com the cost is 10 credits and they will sell you 60 credits (valid for 90 days only) for 6.95