Potato blight and compost

They were ok when you cut them, so I wouldn't worry about them now

As far as I know blight can only survive on living tissue so composting should be no problem especially if there is a bit of heat in the composter someone may know a bit more about it. But if you think about it blight spores come on the rain the rain goes on the compost heap so I don't see how there can be any difference putting you potato tops on the compost heap.

That’s correct, blight spores only remain on living plant tissue so composting the haulms is not a problem

I don't compost even healthy looking potato haulms because early blight spores can easily overwinter in compost heaps which don't heat up enough to kill them, and I don't find it easy to be 100% sure that the various lesions on the dying leaves weren't caused by it.
Some food for thought from the RHS regarding late blight survivability:

Quote

The presence of new blight strains in the UK means that the pathogen now has the potential to produce resting spores (oospores) in the affected plant tissues. The oospores are released from the rotting tissues to contaminate the soil. These resting spores have yet to be found in the UK, but analysis of the recent variations occurring in blight strains in some parts of the UK suggests that they could be being produced. Little is currently known about their survival and their potential as a source of the disease, but investigations are continuing and more information is likely to become available over the next few years. However, because oospores are resilient structures, if they are produced in infected foliage it is quite possible that they will survive many home garden composting systems.

Source: https://www.rhs.org.uk/advice/profile?pid=217

Interesting that JayG I find it incredible that there is not a usable fungicide available to the domestic grower because there must be for farmers. I am lucky I have a saviour which I and every wine grower in France and probably the UK can use. I find it frustrating that it cannot be used in the UK because if used properly the effect on the soil organisms is minimal of course timing is everything. I only use 50 to 80g of the stuff total per year producers use tonnes of the stuff