chassis component or body support?

Anyone know how landys bolt together?

At the back of a crew cab there is a bolt on cross member attached to the top of the ladder chassis (so maybe not part of the chassis for MoT purposes?) that has more corrosion that I'm happy with? Does anyone know the part number for this, where to get one, and what has to be removed to change it - I guess the tub, but don't know if it can easily be done with the cab in place.

Help and suggestions appreciated.

Is it the gearbox crossmember? A round lookin' thing?

Thanks for the reply. Its not round - its a 'C' section - and is several feet behind the gearbox crossmember. The tub sits on supports that are fitted to it. Hopefully the attached pictures upload and can say a thousand words.

the rear tub will have to come off and also the back of the cab as i dont think it will have enough flex in it.

Thanks Adz. I just need to make sure I buy the right part first