You don't say where the boat is or how big So I don't know if that is cheap or not. I had my stinkpot coppercoated (or what ever the name is) about 4 years ago and have not had any problems at all, no maintenance and no fouling but it is lake based, my sailboat if antifouled with Micron Optima which has lasted 2 years with no fouling and is sea based, have thought about copperbot for sailboat but am about to recoat with optima since I don't know how long I am keeping her. I know that my limiting factor is that a hawlout is required re anodes every 2 years at the maximum.
Sorry it doesn't give any straight answers, but I would talk to the locals and see what the experience is.
I used Copperbot, which may be different, some years ago and it was OK for about 6-7 years after which it seemed to drop off in performance. It has however left me with a good waterproof barrier which seems to take antifouling without any primer quite happily. I now use an erodable antifouling and dont worry about it wearing off. Takes a lot of work to prepare the hull.
I puchased enough Copperbot to coat my hull. I had so many problems with the application that I finished up only doing the keel. This has been on for three seasons now, adhesion to the epoxy substrate has been a problem. Fouling control seems to be good. The colour is horrible.
I would definitely not do this job myself, there are so many potential problems and you are dealing with an expensive material that needs a lot of experience to handle well. I know of very successful applications on boats in far higher fouling areas than UK, e.g. Med and Caribbean. These were all applied professionally. Go to someone who knows how to handle it and get a guarantee before agreeing to the job. This adds considerably to the cost, so you then need to consider whether the savings are worthwhile. I have gone back to conventional antifoulings.
Coppercoat seems to cost approximately twice that of a good quality conventional anti-foul such as Micron CSC. Therefore, as long as you are confident that it will last at least two seasons, you will save money. I have yet to hear anyone who has actually used Coppercoat say that it only lasted 2 years - the common concensus would indicate an average life-span of between 7 and 10 years. I had it on my boat in Poole for 6 years before I sold it and it was working perfectly when I handed her over. Seems to me to be the only financially sensible option in the world of anti-fouling these days.