Vayama.ie changed our flight now unable to go on holiday

Getting from Heathrow to Gatwick is not complicated? Elizabeth line to central London then Gatwick express?

there’s busses from Heathrow to Gatwick. Or ask them to change the Irish leg to Heathrow about 50-55 mins from T5

https://www.nationalexpress.com/en/airports/heathrow/gatwick-to-heathrow

Travellers frequently make this connection. MCT is 3.5 hours. What are you arrival times and departure times?

firstly, the Elizabeth Line and the Gatwick Wxpress do not intersect, secondly the Gatwick Express is generally the worst route to Gatwick. Farringdon would be an option to change for the Elizabeth Line to Thameslink although not all of these go to Gatwick.

OP: is this because Aer Lingus has cancelled its LGW route? Can you get them to rebook you onto the BA route (operated by Emeral Airlines). Alternatively, if you have a lot of time and want a simple option, there is a transfer bus between Heathrow and Gatwick.

You will need to transfer your own bags so take account of this.

A prebooked minicab would take an hour and cost approximately £60.