With the days allegedly not getting higher than 14C on the East Coast (and everywhere being pretty chilly anyway) we find that we need to keep the CH on to maintain a reasonable (for us) temperature.
Previous years we have turned CH off in April.
Noting:
(1) We could wear woolly jumpers and thermal underwear indoors and get dressed for bed but comfort is our benchmark.
(2) The house is reasonably well insulated and we do have thermal gain from the South facing rear so it is mainly evening and morning temperatures.
We are with those who leave the CH on thermostat because cold is cold whatever the month.
I don't recall this cold weather at the end of May in any recent years. Those away from the East Coast may be toasting, of course.
Cheers
Dave R