Hey thanks Pastor, might message Spaniard - ah another poor soul who lives the furthest point from the sea possible in the UK!
Thanks Gbguad too, that's really useful info cus I was considering Cagliari just cus the photos look great. I saw a clip on youtube of some bikers going from Alghero to Bosa and the coastline looks pretty sweet so maybe we'll just opt for a little apartment in Alghero and hire a car.
Seems there are a lot of places around Alghero which are just ports (porto ferro, porto torres etc) and just look like a load of concrete and boats

will keep hunting and post what I find.