Resources
Music Minds Matter + Music Support.org
Two separate options that offer a helpline to musicians to call regarding anything that is getting on top of you or just to talk. Sign posting and potential funding for other services such as therapy/rehab/treatment facilities. Music Minds Matter is direct to the source as it is also a funding trust (musician's benevolent fund).
https://www.musicmindsmatter.org.uk/
Counselling-directory
Very handy for finding nearby counsellors. Qualifications are shown and keep an eye out for BACP approved counsellors. Strong explanation on therapy types too.
https://www.counselling-directory.org.uk/
Cheaper/free counselling options
NHS - offering particularly CBT, though will may take longer as it's in high demand.
https://www.nhs.uk/conditions/counselling/
Teen Counselling.com - ages 13-19, online counselling at cheaper rates
https://www.teencounseling.com
Betterhelp - Online therapy for all, a few options, convenient and anonymous
British Association for Performing Arts Medicine (BAPAM)
A healthcare charity giving medical advice to people in the performing arts. Help to overcome work-related health problems, and can include consultations with mental and physical experts