Have you considered renting a car?
You could get a decent car with snow chains and insurance for less than £200.That is what we decided to do because the cost of transfers for 6 of us is prohibitive.
Share transfer cont
Trevski
Found for 580 Euros a 8 seater taxi RETURN 15th Feb Barcelona Arinsal - Arinsal Barcelona 22nd Feb, thus party of up to 5 required to share transfer!!!!! Happy to pay half (for 3 seats) 290 euros just to get a direct route to arinsal directly after getting off plane and not wait for the bus with the other million people trying to get on it!!!