Linear is the best choice, try Brasenose 1, contact them first to make sure the lake is open, they have a website. Get there early to claim a swim as it does get very busy,even mid-week.
Milton Pools sound like a shadow of their past, I've read many a bad report concerning fish kills,unsociable behaviour from management and clients and general lack of etiquette mixed in with a large lump of argy-bargy.