This hotel has a something like an executive lounge. It appears that snacks and alcoholic drinks are complimentary. It doesn't say when they close in the evening. Also, not sure if the complimentary food will be kid friendly, though I'm sure you can just pay separately and order from the in-room dining menu and have it served in the lounge:
https://www.athenaeumhotel.com/the-view/

This hotel sounds like a glutton's dream (including myself). However, the only drinks that are complimentary is the welcome glass of champagne at check-in and water throughout your stay. Also, the evening food timings may not be ideal for your kids unless they usually eat very late:
https://www.41hotel.com/food-and-dri...mentary-treats

This hotel has a proper executive lounge. It appears that alcohol and food is complimentary all day long. However, they don't say on their web site when they close in the evening:
Luxury 5-star Hotel Club Lounge in London | The Langham, London