I'd (for example) you'd left it too bloody late to get a reasonable price on a half-board hol abroad at May half-term, what would be the closest UK equivalent in terms of convenience/ease? I think the best thing for me about half-board or AI in a family-friendly hotel is not having to think about meals and having stuff to do on-site - usually pool, ping pong, crazy golf etc for us. We also take my parents who enjoy sitting in the shade watching the kids in the pool and playing endless Uno etc.
What could you do in the UK for a bot crazy-price that would have a similar feel/sense of relaxation? Obvs not Center Parcs as I haven't come into money. Is that basically the only alternative really though? Although even there you have to plan ahead and book restaurants and activities etc.