Sorry no experience of Portugal but if you google the thread two informative links come up. I don't know how to create a link for you - www.aboutdrivingabroad.co.uk/dr is one, www.fodors.com/community/Europe is the other.
Good luck!
Thanks Ruth you really should try Portugal great place and people.The north is good and the Algarve is good in parts.I will have to sort these tolls out when we arrive!
Amazing family weekend with old steam engines, classic car displays, market stalls, and full catering and bar. And camping on site - Save £25 by booking in advance.