exhaust and cat question ?

When my TF failed its MOT on exhaust I naively just bought a new rear box and set aside a couple of hours. I soon realised the flange on the cat was knackered where it bolted to the back box. I doubt I can remake the flange so I presume it has to be a new cat.
However I also then realised the pipe in front of that was loose, where it comes out of the flexible section. So:

1. Is there a trick to remove the sensor from the cat so I can save the sensor . It seems impossible to remove on the car with nothing now rigid enough to be able to apply a proper amount of turning force. Is there a connector at the other end of its lead I can separate so I can at least get the remains of the cat off and have a go at separating the sensor on the bench ?

2. Is a decat pipe and a MIL eliminator circuit more practical or is this something most MOT centres wouldn't tolerate ? I'm used to working on much older classics so never come accross this before. I'm aware some people on here have decats.

3. The length of pipe with the flexible bit in. Is this supposed to be a single piece. Does it separate anywhere or will I need to replace it between the exhaust manifold and the cat as a single unit ?

Unless you have a different manifold the flexy section is part of the down pipe which the conects to the cat then back box, I removed my lambda sensor by holding it in a vice and turning the cat ( once removed obviosly)

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I will try that. Do you know where i can connect the other end of the sensor lead please. I cant see where it goes

It's a three pin plug around the area of the ecu. You will need to get the engine cover off to get to it.

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Thanks. A new cat & flexi pipe and gaskets are on their way now.
Over the next couple of evenings i'l have a go at separating the remains of the old flexi pipe from the manifold flange and disconnect the lambda sensor top connection so i can get the cat on the bench and hopefully liberate the sensor for reuse.

Ive just seen there is a special slotted socket available for removing the lambda sensor which should hopefully be safer and surer than using a spanner or having to cut and rejoin the lead which would be the way with a regular socket. No doubt after 10 mins use it will go in the bottom of a dusty draw with the huge 1 &13/16ths socket ive ordered to tackle the N/s front top ball joint, an MOT advisory or the crows foot spanner I bought to tighten the inaccessible front wishbone bolt.
It goes against the grain buying tools that may only ever be used once or twice but the reality is it is an awful lot cheaper than paying a mechanic to do those jobs just because i dont have the tools

Pleasantly surprised how easily that all came apart yesterday evening. The manifold to downpipe nuts were easier to get at and easier to undo than i had hoped.
With the remains of the cat and then the front pipe in a vice both the lambda sensors yielded to a bit of mild force and a 22mm spanner.

The new cat, 2nd hand downpipe and gaskets have just been delivered so thats this evening taken care of. Brilliant service from Darren at Mgfntfbitz again as I only ordered them yesterday.

Im assuming the lambda sensors can just be reused but if i do need to replace one does anyone know why the price of them varies so much ? Ive seen compatible lambda sensors range from £ 18 to over £ 60

Price difference due to
Cheap chinese crap not working properly, failing after 50 miles.
Expensive Japanese or German brand working properly.

I tried a cheaper one on my Old Nissan 200. Lasted about 2 miles!

Just buy a bosch! No point in any other.

Not all Bosch is beyond reproach, I’ve been repairing my sister in law’s Chinese manufactured vac & the board is glooped with a silicone compound liberally slopped over the devices which are the most likely to fail, one of which has. Further research has taught me that the failed device is only listed by one supplier, with a minimum order charge we’ll in excess of the vacs value.
Your bin or mine?

Only speaking lfrom past experience and the wise words of Jon from Rough luck.

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No one with an ounce of common sense would even contemplate arguing with Jon, it’s a shame he doesn’t supply motor control parts for vacuums!

Is it known if the pre and post lambda sensors (front pipe and cat) are the same types or if are they are non interchangeable ?