Problem with Lease and local Council

[OsborneG]

Our charity trust administers a sports ground as some buildings given for the use of the local community. Trust deed states "to hold the same unto the council in fee simple for the purposes of a public playing field......" Another clause says: "The committee shall provide the council with sufficient funds to meet all expenditure (if any) in connection with the Trust premises as the council may be liable for and shall keep the Council indemnified against all liability (if any) in respect thereof.” For the first time since 1906 the parish council has decided to charge us for maintaining the grounds using the above clause as the excuse. The grounds are available for the public and sports clubs to use in exactly the same manner as the other open spaces maintained by the council. Is the council correct in using the above clause as the excuse to extract fees from us, they appear to be saying that they can extract any sum they want?