Using the Wordpress framework a page would be easy to construct. This page could include a simple contact form that the person "subscribing" could be contacted with a "free-form" query. This does not need to be a detailed e-commerce order form but just an effective way of matching up the advertiser and the customer.
I am not suggesting that I take this initiative. It is still a lot of work for a questionable return, and the Village Hall really doesn't need the money as it recieved a £10,000 grant for Covid relief.
At the present time the advertising on the Fscebook pages consist of photos of business cards and some of products. Menus from local pubs and meal services are also posted. In the later cases the communication method is not optimal in that some responders post comments on the post to make a reservation. This is confusing to other viewers and other than the person making the reservation don't need to know! Sure, there is a PM facility built in to FB but I am not convinced that most of the users know how to do this.
A simple form would establish a direct email interchange between the advertiser and the customer. In the case of a reservation the customer can pick items from a menu, specify numbers of guests and times that the booking is required. All Facebook users have email addresses and this also builds a customer base for the advertiser. Alternatively a simple telephone call can be made!!!
There is a big difference between an honest request for a recomendation for a dog grooming service and an ad placed just because you can (and it is free!)
This does not need to be complicated and apert from the basic contact details, name and email, the rest can be achieved with a simple text field. The form is similar to the Contact the Hall page.