No. You can be any age - old or young - as long as you have a valid driving license and you don't have any health conditions which affect your ability to drive safely.
Yes, usually. You will need to notify your insurance company, but this should not affect your premium.
If you drive a minibus for a local scheme or community group you will be covered by their insurance.
No. Your expenses will be reimbursed.
Unlikely, unless your total mileage driven as a volunteer is very high.
Unlikely, because you will only receive payment towards expenses.
It may be wise to check though.
Yes. As you may be in contact with vulnerable members of the community, a Criminal Records Bureau Disclosure will be required. This is free for volunteers. You'll be given further guidance about this when you apply to become a driver.