Fault code P1190

Hi, I have the following fault code on my mk4 golf, AUS engine. 17598 linear O2 sensor, reference voltage implausible. P1190 35-10 intermittent. Could anyone please advise? Is there 2 O2 sensors on this engine and if so do you know which one is faulty and a rough price to replace? Also any particular make I should look for. Thanks in advance :)

It's the precat Lambda sensor the one on the exhaust manifold. Genuine is around £100.00

Thanks for your advice :)

Sorry I am having imagery flashes, do you resemble Tallulah Bankhead?