Didn't realise you hadn't actually gone yet!

We are flying with monarch and i asked if we could take excess baggage and you can't pre-book it, just pay £6 per kilo at the airport so they gave me the number for TFA logistics, and you have to pre-book it at least 3 days before travel and give them the aprox weight and dimensions of your boxes. they charge £2.50 per kilo with a min £120.

you have to take the boxes to the airport 5 hours before the flight and pay for it and then collect it the day after arrival at the other end.

If you're not taking a huge amount, this option might work out cheaper and easier that having to look at shipping companies. it also worked out easier for us as we can still use our belongings up until we go and don't have to do without them for weeks while they're packed up/being sent.