Just accept that everything notified in the UK Air Pilot, notams and any other CAA document is UTC, unless otherwise published .
That's the way it is, has been and always will be.
Take care when utilising pooleys etc, sometimes times are given in local in these documents, but the publishers usually go to a lot of trouble to make it obvious that they are.
HWD - if you want to send a notam but don't know how, contact AIS at Heathrow, they're very helpful.