Please avoid travelling on the day of the wedding, as you may not make it in time if there are any delays.
PAY FOR YOUR SEAT!!
Speaking from experience, when booking your flights we advise that you pay the extra to secure your seat. If you do not pay for your seat, there is a chance they can put you on reserve (this is because airlines oversell flights, so anyone that has not pre-paid for a seat, is not guaranteed to get on the flight).
Keeping the cost down - purchasing 1 hold luggage and sharing it between you can save a lot of money.
Wizz Air - Via Luton
Book the basic option and add luggage later to get the cheapest option possible.
Easyjet - Via Gatwick
These flights have currently been cancelled, but they may be re-released soon.