Drat! Denis you are a star....I should have thought of that, yes if I follow your suggestion and enter the full URAT1 Id as previously if fails 'Object not found' rather than 'Not a valid object'
But.....if I just enter the the numeric part i.e. 425-014969 then Guide finds and centres the object.
Hopefully now other may find this useful, many thanks for the assist:)
very best regards
stjohn