London with toddler

[Cuwins]

We are thinking of taking our nearly 3 year old to London for a day this week. She has never been, we are about an hour away on the train- she will love the train and we are reasonably confident getting around although never done it with a buggy!
She is very in to Christmas decorations etc this year so we are thinking she would like to see some of the big ones in London.
Where would people suggest we go?

Regent Street and Hamleys, busy though

Anywhere but London. It’ll be heaving everywhere. Hamley’s, Harrods, Fortmun and Mason will all be shoulder to shoulder and not somewhere I’d try with a buggy.

DH used to work in London and every year around this time I’d get the idea that this sounded like fun, and fully regret it half an hour after arrival.

That's a shame I was hoping during the week in the daytime wouldn't be too bad. Will have to think about it. Thanks