I offer a menu of freshly cooked ready to heat meals for guests in my holiday cottages - the menu is seasonal and based on locally produced food, for example at the moment I'm offering things like creamy asparagus soup, slow cooked pulled lamb, rhubarb & strawberry crumble. (I also cook at the cottages, kind of like a dinner party service). It's very popular with my guests, but in my experience they are looking for something more than lasagne or shepherds pie, which they could get delivered from waitrose or tesco.
I also offer a light supper hamper for people arriving late at the cottages (a bowl of salad, home made bread, cheese, ham and fruit) and a starter breakfast hamper (usual things like bacon, eggs, sausages, cereal, croissants, etc) These are extremely popular, particularly with guests coming from overseas.
I always provide a cake or similar together with good supplies of tea coffee and milk to all guests - invaluable if guests have had to sit in traffic or travel a long way!
If you are planning on providing food, I think that you do need to have a food hygiene certificate (but you can do this very easily on the internet) and sometimes you need to have your kitchen inspected. Also the rules regarding the storage and onward sale of frozen food are quite strict (separate freezers, monitoring of temperature required, etc) which is why I opted for the fresh meal approach.
We've had loads of repeat guests as a result of offering food - it's well worth doing it! Good luck!!!