I had the same issue with the oil pressure switch! it had been leaking for ages and meade a complete mess of the engine bay and air con pump! all cam off with a steam cleaner though!
Anyway, interestingly i have exactly the same codes as you, do you have any driveability problems? mine bogs down and is sluggish, im suspecting a fuel pressure issue as ive fitted a brand new MAF and cannot find any vacuum leaks, engine vacuum seems OK as its very difficult to remove the oil filler cap with the engine running.
Im busy buying gaskets, timing chains, chain guides, water pipe etc... to overhaul the engine in the new year, strip heads, re-cut valves and seats, fit new valve stem seals, clean secondary air inlet ports etc.... will swap out the O2 sensors too and hope for the best!