If your action requires matching or selecting a UK GPs - especially if you use tailored messaging and/or merge fields - then further testing is advised.
Why?: the wide and growing range of recipient lookup (and supression) plus message tailoring options means it is easy to have incorrect settings.
UK GPs are matched by the sender selecting their GP or GP practice from a shortlist. GPs can be shortlisted by the sender entering in their own postcode (if the practice is nearby), the practice postcode, the GP's name, the GP practice or the city.
Test for negative results (e.g. mispelled name, partial/invalid postcode) not just for positive but for results that should be negative.