Steve, just do as we do, stick it under your arm and just check it in with your baggage allowance.
Check with the airline first as different airlines have different limits to the maximum weight of a package.
I know TC and onur have a limit of 30kgs for a package, but Thompsons (first choice) their limit is 25kgs.
remember your baggage allowance is combined weight so if one parcel is over the others can be under and no charge should be levied as long as combined weight is not exceeded.
It may also be cheaper if your combined weight is exceeded to pay the excess rather that paying £100+ depending on how much you are over.