ParcelForce Worldwide will do this for you. You can do everything online, and they'll come and collect your package if you want them to. Otherwise you can make the arrangements online and take the parcel to a Post Office or ParcelForce depot.
There'll be a 30Kg weight limit, and the package will be delivered in Malta within three days. There's a next day priority service, but that costs more.
The cost of the 3 day service will be around £28, plus a collection charge if you opt for that.
Size of the item would also determine the price, and some companies have strict size limits.
I have used DHL on a few occasions, who will collect, pack and do the necessary form requirements for you. The driver would want to inspect the item first, so that they can verify the actual item being sent, for clearance purposes. If you have a Staples store near, then check if they will send, because they do act as agents for DHL here in the UK. Not sure if they will do larger export items though, but they should be able to advice.
One thing that I would perhaps suggest is try a simple Google search by putting "sending parcels to malta' and it should bring a number of possible solutions and link quotation forms for instant response. Parcel Monkey and Parcel2Go use to be reasonable, but strict size and weight restrictions would apply with them.