Oh dear...
 

Heard a rattle and it was this....

https://farm5.staticflickr.com/4325/...63bb256f_z.jpg

https://farm5.staticflickr.com/4324/...9f952bf7_z.jpg

OOOOps.....Not exactly cheap for full assembly 40-60 quid new ...Maybe a fabrication job would be cheaper.

All you need is some slotted metal strip,,and readily available from any good DIY store;)

Get the galvanised stuff then it won't rust...

....and when you need an aftermarket replacement back box , they come with hangers welded on so you won't need that strap anyway .:}
A bit of fence wire will do for now ....:getmecoat:

Galv steel banding.
Hundreds of uses. Available from toolstation.
Just cut it to length and shape it.
:smilie_re:http://www.google.co.uk/shopping/pro...yABEgLACPD_BwE

if the exhaust is fine the brackets are available on Rimmers

Items 11 and 12.

https://www.rimmerbros.co.uk/Item--i-GRID001949

Tried to get the broken bits off today, but the bolts and nuts were rusted solid. Used plenty of penetrating fluid but no joy. As suggested, I may well try wiring it as a temporary measure. The box is quite rusty in places, although not so bad that it necessarily needs replacement yet, but will do soon, so I might go the whole hog and get it done.

Yes, that was my Plan A: undo two bolts, old bits off, new bracket on, easy-peasey .... but as per previous post, no such luck!

Corrected that for you...

"Get the galvanised stuff then it will take longer before it starts to rust"