VCDS method of finding oxygen/lambda fault?

Hi folks. Well I'm sat here totally at a loss as to how to trace which of these o2 sensors are goosed. Here's my VCDS log:-

Address 01: Engine Labels: 4D0-907-560-AVP.lbl
Part No: 4D0 907 559 AA
Component: 4.2L V8/5V G 0002
Coding: 10753
Shop #: WSC 02313
4 Faults Found:
16814 - Catalyst System; Bank 2: Efficiency Below Threshold
P0430 - 35-00 - -
16804 - Catalyst System; Bank 1: Efficiency Below Threshold
P0420 - 35-00 - -
18047 - Accelerator Position Sensor 1/2 (G79/G185): Implausible Signal
P1639 - 35-10 - - - Intermittent
18047 - Accelerator Position Sensor 1/2 (G79/G185): Implausible Signal
P1639 - 35-10 - - - Intermittent
Readiness: 0000 0000

Address 03: ABS Brakes Labels: 8D0-907-389.lbl
Part No: 4D0 907 389 E
Component: ABS/ESP allrad D56
Coding: 08397
Shop #: WSC 02313
1 Fault Found:
01119 - Gear Recognition Signal
35-10 - - - Intermittent

Address 17: Instruments Labels:
Part No: 4D0 919 035 BA
Component: KOMBI+WEGFAHRS.VDO D39
Coding: 00483
Shop #: WSC 02313

No Faults Found or DTCs not supported by controller or a communication error occurred

Address 56: Radio Labels: Redir Fail!
Part No: 4D0 035 192 M
Component: Radio BNO 0001
Coding: 00117
Shop #: WSC 00726

1 Fault Found:
00852 - Loudspeaker(s); Front
36-00 - Open Circuit

I checked with the place that did my cats, they haven't sold or fitted 100cel cats for about 6 years due to MOT failures and too many customer complaints. So I'm confident the cats are 200cel.

I'm about to delve into VCDS measuring blocks to see if I can suss out which sensors are giving out dodgy readings - anybody know what I should be looking for? I did a trial run earlier and had a look through all the different readings and blocks, so I've an idea where to look now, I just don't know HOW to look and WHAT to look for

I've got Elsa on the go now so I'll report back if I find anything.