EDIT - I FOUND THIS

https://www.moneysavingexpert.com/shopping/cheap-theatre-tickets/

A bit of a longshot here, but I’m looking to buy my nephew and his girlfriend tickets to ‘Elf’ in London for a Christmas/early Christmas present.

https://elflondon.com/?gad_source=1&gad_campaignid=17067106548

Tickets are a lot more expensive than I was expecting unless I get them tickets miles down the back. Are there any specific sites that those ‘in the know’ use to get better placed prices or codes for something like this?