From mid-morning tomorrow, Wednesday 6 September 2017, the UK Coastguard will no longer broadcast on VHF 23, 84 and 86. Instead it will use VHF 62, 63 and 64. VHF Channel 10 for MSI and pollution control (back up) will remain the same.
MSI broadcasts are announced by the Coastguard on Channel 16 enabling seafarers to establish which channel to monitor. However, the MCA has also provided a list detailing which aerial will broadcast on which channel which you can view on the RYA's website here: MSI Channels.