Questions ?

No, you would need to hold a level 3 Certificate in Personal Training (or equivalent) to be able to be insured as a personal trainer
Yes, for our level 2 gym instructor, exercise to music and our level 3 personal training courses we offer payment plans. The level 2 courses involve an initial deposit of £100 followed by minimum monthly instalments of £100. Our level 3 personal training course involves a minimum deposit of £200 followed by minimum monthly instalments of £200. Certification could not be made until the full amount is paid.
Yes, it would not be possible to qualify in one of the CPD courses without the minimum requirement of a level 2 Cettificate in Fitness Instructing (or equivalent) as the pre-requisite. Where it would be possible for anyone to attend one of our CPD courses for their own knowledge, the certificate would not be valid without the relevant pre-requisite.

Training

No, you must hold a qualification for exercise and physical activity for children, this is the only children's fitness qualfication recognised by REPs. Your personal training insurance will only cover you for the specific qualifications you hold.
You must contact the land owners to obtain their permission for running boot camps on their land, most councils in Scotland will allow you to teach boot camps in some public areas without charge as long as you have cleared it with them first. However, they would most definitely charge for areas such as country parks, country estates etc.
No, you must have the gym instructor qualification as the pre-requisite for the level 3 Certificate in Personal Training