Party wall agreement and sale

[YellowSunRays]

Following on from a thread I've just read regarding a possible issue with a party wall agreement, I'm looking for some advice please.
Planning to sell next year and since we bought our house, our neighbours have built an extension, on footprint of old conservatory, which also incorporates a partial conversion of their garage at rear.
As far as I recall, as it was done at least 5 or 6 years ago now, they didn't need planning permission because it didn't increase the footprint of the building.
Our houses are link detached, main house detached but garages linked and so our garages share a wall.
This means their office conversion has a shared wall with our garage.
I wasn't overjoyed at the time as it means they now have living accommodation right on our boundary, which obviously wasn't the case when it was a garage, with a window right next to our fence.
Have got used to it but now I'm wondering whether this will affect our sale?
Should there be a party wall agreement and would searches, etc raise an issue with this?
If so, what do I do now to prevent an issue with the sale?
Many thanks in advance for reading through this!

It's all a bit too late now. The whole thing with the Party Wall Act is to protect both sides while work is being done on a party wall. It isn't intended to prevent the work being done.

"...and so our garages share a wall."

In any event, it all depends what work they were doing. So, for example, if they had cut into the shared wall to insert a damp proof course or knocked out some bricks to put in an RSJ then the party wall act would be engaged.

But if they just put up some plaster board or affixed some cabinets to the wall then that would not be covered by the Party Wall Act

"...with a window right next to our fence."

You can have a fence up to 2m (6'6") tall. That should be tall enough to stop them looking out over your garden if that is what you are concerned about.

" ...but now I'm wondering whether this will affect our sale?"

Not at all

"Should there be a party wall agreement and would searches, etc raise an issue with this?"

Whether there should have been or not before the work commenced is irrelevant now as the work has already been completed.

Your neighbour converting their garage to living space won't raise any issues for you.