Party wall act & survey

[Icyblue]

My neighbour is building a rear single storey extension so will be knocking down their garage and digging a foundation. The garage is right next to our garden and the neighbour has agreed to replace it with fences. We've received two letters from surveyors (random surveyors which are unknown to us) advising us to contact them to act on behalf of us in case there is damage to our house while work is being taken. Is it necessary to contact the surveyors as the fee is being charged to our neighbour? How do I go about it or do I ignore the letters?

This is a pretty well-know scam...
Firms of surveyors trawl the planning database, and whenever someone has been award planning permission, they write scaremongering letters to the neighbours, suggesting they must be appointed.
I wouldn't appoint any firm that canvasses for business in this way, but it isn't really possible from your description of the work to tell if a party wall agreement is actually needed.

Do you get on well with your neighbours? Would they put right any damage caused by their buildings works?

Hi sparechange, one side of their garage is our garden wall. Once it has been knocked down they will replace the missing wall with wooden fence. So basically there is no party wall between the two properties as the garage belongs to the neighbour. The surveyors' letters was saying that because foundation is being digged within 10m of our house, we need to safeguard ourselves if damages do arise.

They have moved in about six months ago. We don't know them well but they seem reasonable people.

These letters are from the equivalent of ambulance chasers. Ignore them.
Neighbour should have approached you about their plans though, ask if you can see over them (just to reassure yourselves re drainage etc)