VHF conditions up?

We normally hold an East Cambridgeshire net at 1900z Mondays on 144.575MHz FM. If the channel is busy we move down 25kHz or further.  This evening it was busy so we moved down to 144.550MHz FM. G4CPE (Luton) was a "smooth noise" signal with me working G3KKD.  Next week we will be back on 144.575MHz FM all being well.