Is a holed exhaust always a fail?

Or can it patched to get through the test?

So long as it’s airtight it will pass. Either seam weld it up or get a kit from Halfords etc to patch it up.

Local Ford dealer suggest close to £300 for a new exhaust during pre-MoT service. Hole is smaller than my little finger nail

Can be patched and still pass the MOT.

patch it but dont expect it to last

patch it but dont expect it to last

Don’t need it to last – just dont want to pay out for pads, tyres and exhaust all at one go.

Depends on the size of the hole.

You can repair it with sealant (not just any sealant, it has to withstand high temperatures), try Gun Gum or some other brand from Halfords.

Note that the MOT tester is likely to poke your repair with his ‘poker’ (not sure if that’s the official term for the tool, but it looks like a fat, blunt screwdriver with a handle!). So if you do a crappy job of repairing it, he might still fail you!

With any question like this, it’s worth asking your MOT garage in advance.
If they’re offering free retests they would probably rather spend 5 minutes giving you some advice in advance than half an hour going through the full retest procedure afterwards.