If render is cracking off a wall what do i need to replace it with ?

Have you considered asking the neighbours what they have used?

Or is the whole terrace rendered?

There are breathable rendering(s) out there, but first of all, you really need to remove all old pebbledash and see what state the brickwork is in. It'll also help dry out the brickwork as we are going into spring/summer right now.

Some of that stonechip stuff that was done a few years ago was rubbish I'm afraid. My own house built about 100 years ago had the similar stuff on which was flaking off when I bought it. I removed the rest of it and found that there was some good lime render underneath. I then just smoothed it down, did the odd repair here and there and re-painted it with Dulux Weathershield. That was 7 years ago and it still looks great. Please note that houses built at that time were built with lime mortar which is actually superior to modern cement although it takes longer to set. This means that if you decide to have it re-rendered, you should use lime based render rather than cement and have it done by someone who knows what they are doing. Lime render is so superior to cement render that it will last for many years and there are a number of old houses around the UK where it has been in place for hundreds of years. PS that surveyor is talking rubbish.

You taught me a new word-- "render," meaning a layer of cement mixed with sand, gravel, or small stones applied to the outside of a wall (I looked it up).

Walls breathing is a concept I'm not very familiar with. Most walls are meant to be water-tight, and fairly air-tight as well (for insulation purposes). Modern house walls have a vapor barrier to keep moisture out, but this may not have been the case in the 1800s.

In other words, I don't know the answer to your question, but you've given me something to think about.