UK driving licences are recognised in Majorca as well as all all other EU state driving licences. If you live outside of the EU then you will require a 12 month international drivers permit (IDP) in addition to you licence. However licences from America, Australia, Canada and New Zealand can sometime be accepted by car hire companies so it is worth checking before hand.
In Majorca you drive on the right hands side. In built up areas the speed limit is 50 km per hour, on main road it is 100km/h and on 4 lane motorways this rises to 120km/h.
If you are riding a motorcycle (125cc +) you are required to wear a helmet at all times as well as keep your lights on.
Breath testing for alcohol is becoming more common and the blood alcohol limit is 0.05%. If you are driving then it is best to avoid alcohol as fines range from 600 euros up and non residents are required to pay up front.
Other useful info