Not sure if this is much use to you Paddy, but the Aircoach service offers a crew rate of EUR 3.00 each way. Have a look at
www.aircoach.ie for route info, it all depends on where your coming from in Dublin?
There is also a new long term car park in Santry with a daily rate of EUR5.00.. not sure if they offer a crew rate though (
www.quickpark.ie)
You could also try Aer Rianta, they must have a some option for commuters?
Be careful of the Aer Lingus car park if you do manage to get in, the clampers are often about - not the best thing to come back to ater a long trip.
All the best with the move home