I think Connells only handle CAM. http://www.solvia.es/ handles CAM as well along with Sabadell and maybe other banks as well. http://www.altamirasantander.com/ handles Santander, https://www.bbvavivienda.com/ handles BBVA, and you can find links to most other Spanish bank property listings from their respective web pages.
I think it is generally better to deal directly with the bank if you can, as that allows you to cut out a middle man.
Pretty much all these repossessions will be listed on http://www.idealista.com/pagina/portada anyway, which is an excellent site that also indicates price changes, and allows you to filter specifically for repossessions (“de bancos y cajas”).
If you use Rightmove then you must use the http://www.property-bee.com/ add-on for Firefox. It will magically display the price history of listed properties and give you a good idea of how long a property has been on the market (essential information)