Direct flights to Lisbon are available from London airports and some major provincial airports.
Once in your car it is 2 minutes from Lisbon airport to duel carriageway going North. Make sure you have Euro coins with you for the tolls.
If your stay is longer than a week consider flying via Faro which is generally cheaper but involves more travel once landed - 250 miles on either motorway or duel carriageway.
Driving
If you are taking a longer break and prefer to drive it's a journey that can be made with a couple of overnight stops. Try a pre-booked Spanish pousada on the way for a treat.
Ferry
Plymouth to Santander is a 17 hour cruise with 500 mile road journey to the cottage.
Euro Tunnel
Turn up and go or pre-book.
Car Hire
It is important to pre-book your car from the UK so that it is waiting for you at the airport. All major hire companies operate from Lisbon.