Thinking of doing a motorhome road trip for a couple of weeks in Portugal Sept / Oct.... Any info on spots, wind, weather, camping facilities would be greatly appreciated

Sept/Oct: great weather, but the windy season is usually gone which is more like May to August.
Great time to go surfing though. You should definitely include Guincho beach/Cascais (close to Lisbon) on your list. They have a big and nice camping ground close by.
You should take an SUP/Surf or bodyboard with you.
Full wetsuit steamer 3/2mm as the water is cold, around 16°C in summer.

Check locations on www.splocs.com

And download the free app ! Search for "splocs"

Then get a port. SIM card and the app will be a great navigation tool!

And pls make pictures of the locations in the way and upload them via app to the site!

Have a great trip!!!