Hi Clare,
I hope you are well. I have just noticed your post from some time ago. This might not be relevant to you now but I am a volunteer with the Move Against Cancer charity. The charity provides online resources giving advice on exercise to young people (age 30 and under) living with or recovering from cancer.
It also links up with parkruns all around the country on the last Saturday of the month for 5KYourWay where volunteers, people living with or beyond cancer (any age), their friends and relatives, meet at parkruns and jog or walk the 5K route or less. We then meet up for a coffee. The groups are very welcoming and supportive.
You can find out more at https://www.moveagainstcancer.org/
I don’t know if you’re still interested in this as your post was over a year ago, but this may help.
Thanks,
Belle