My insurance is similar price to Hughes for an EC120. Yet there are two problems
First, the excess fee for a low-hrs pilot is £75k. Hence the school needs to be confident that you have the assets - an will pay if needed - the excess should you bend the aircraft.
Best idea is talk to one of the insurance brokers to see what cover you can get for yourself. Then you can see if the school will hire you based on your insurance, not theirs.
Secondly, the consequence of a sizeable claim on the insurance cost of the school may be prohibitive; they might think it could be enough to actually put them out of business (depends on the claims history of the school).