Over the past few days UHF channel 35 from Hemel Hempstead (Bedmond) has been on full power test (200 watts) with no channels carried. Looks like this is the rumoured extension of London Live to Hemel & St. Albans, & will bring official coverage outside the M25 to the North West of London.
OFCOM is showing the launch date as Wednesday 27 March 2019.
http://www.digitaluk.co.uk/__data/as..._London_V2.pdf