We are planning to sail from Ireland to the Iberian Peninsula in June and leave our Valiant 42 (Pegasus VII) there until we resume travels in September.

Does anyone have a recommendation (or warning) for a secure but not wildly expensive option in any of Gibraltar, Spain or Portugal?

Marina Lagos in Portugal is SUPERB on all counts. We overwintered there in 2011/12 and the marina is totally protected with excellent services. Very good boatyard next door and cheap Ryan Air flights to Faro and then train to within 5 minutes walk of the marina. The OCC Port Officer is equally superb Terry O 'Brian! However I do think that it gets pretty full in the summer

If this is so then try Porto de Nazaré. Most ports on the Atlantic coast suffer more or less from swell, but Porto de Nazaré is renown for being free from this.

We have cruised up and down this coast and would be happy to help you with any other questions.