Website for apartment in Basque country

[ItscalledaVulva]

Looking to stay in San Sebastian and Bilbao in October with a large group, wanting apartments in town rather than villas in villages for various reasons.

I've looked on airbnb but are there other websites anyone would recommend for owner-rented apartments in Northern Spain?

Holiday Lettings or Booking.com?

Many thanks, I'll take a look!

homeandaway is another website (I think they're associated with Trip Advisor). Depending on your level of Spanish you could also try Niumba and Wimdu.