I would advise you to join the BDMA if you want to get into this type of work.
Many insurers have now instructed Loss Adjusters, they and their contractors need to be at Technician status.
Certainly if you are serious about it, then the investment can be high. If you think you've seen a couple of flooded properties and you could do that, throw in a couple of dehums and a blower and charge the earth, think again.
Insurers are only interested in one thing and thats cost.
Some prices are as low as £125 a room, for all your equipment, site visits, moisture maps, photo's, inventory lists. If the room takes 3 months to dry out, you still only get £125!