Have you had a response to your request yet for a mentor? Contact me via the website alexkinnersley.co.uk if not and I would be happy to help via zoom or phone.
There's a very friendly branch in West Mids (Dudley) run by Elaine - have a look on the Forum pages to find where is nearest to you. Since meetings are on zoom at the mo I can also recommend Worcestershire and Gloucestershire branch meetings which I am sure you will find helpful.
All best with your first client - it is nerve wracking and it's great that you have reached out to the ICB community!