Fantastic. Thank you so much everyone.
I did'nt even know there was an Airport at Inverness! Looking at the map it is the obvious choice. I have taken all your advice and fortunately for me, Luton is my local Airport, so I have booked with EasyJet, along with the car from Europcar.
The only downside to it is that there is only one flight a day and it is an afternoon flight, so I would lose a whole day. It's swings and roundabouts though, as I don't have that long drive. I have managed to get an extra day off work, so a five day trip it is. Roll on the 6th March.
Once again, thanks to you all.