Most community centres have to pay their way without the guarantee of a blank cheque from the parish council. Major funders such as the lottery would need to see a business plan that demonstrated the viability of the building before they would consider offering funding. In your case, the future of the facility lies in the hands of 50% plus one of your parish council, not only those currently serving, but any who may follow them in the future. If they pull the plug, the community centre would almost certainly have to close. It's an uncomfortable inter-dependency.
Parish precepts vary enormously in your area, from under £20 to over £80 for a Band D property, so you are mid-range on this scale. The sums of money seem large, but you live in a large parish, so the cost per head is minimal. If my sums are right, your parish council, including the subsidy to the community centre, costs each resident about 50p per week.