Largish hotel with swimming pool in southeast

[SweetApril]

Hi. I'm looking for a fairly large chain type hotel (eg Holiday Inn, Marriott) that has a decent warm pool which children are allowed to use. A "baby/toddler" pool would be a bonus too. Would also need to have an extensive buffet breakfast of reasonable quality. And would be good if there was something to do/visit fairly close by, even if only a shopping centre.

Sounds a daft request but this is DD's favourite kind of treat (swimming, "posh" breakfast, exploring endless corridors and going up and down the stairs and in lifts). We can't afford a proper holiday this year so we're going to take a couple of nights in a hotel. Any suggestions/ideas very welcome. If anyone knows the Marriott in York that's the kind of thing I'm talking about. Thanks!