A5 Sportback Engine fault P246F00 Exhaust sensor error.

HI there, I'm new to the site, I have a 2010 Audi A5 Sportback 3.0TDi Quattro Auto, 60k miles, its got the same fault as explained in a previous thread in July 2017, engine fault light ON and the following fault code, P246F00 & P246E00 Exhaust Gas Temperature Sensor Circuit Bank 1 Sensor 4 Range / Performance. See attached picture.
https://www.vwaudiforum.co.uk/forum/a...652667&thumb=1

My question is what is the part number for this sensor so I can order one and where is it located on the exhaust, I believe I can get it from Euro parts etc, is it easy to access etc, I have it booked in with my mechanic friend next Tuesday.

Many thanks Mark