[bazwaldo]

I saw a period property for sale that am very interested in. There is the odd crack in plaster and some signs of leaks or damp too.

Before I consider making any offer, I'd like to know which people I need to talk to so I can factor in the costs in addition to the house price.

There are bound to be a few issues such as damp/cracks which need fixing, along with rewiring, and maybe some plumbing. The house also needs extending to add a kitchen and an extra bedroom.

Is it a building surveryor for the house issues and a quantity surveyor or a builder for renovating/extending costs?

I assume its best to talk to these before placing any bid.

[archtech]

Engage a building surveyor or arch tech/engineer/architect to undertake a detail inspection survey of the property, expect to pay a couple of hundred for it and you should get a comprehensive report (well in excessive of 3-5 pages) on the property.
It might not be any harm to have arrange to met him/her on site for an initial quick inspection ( for a small (er) fee) before proceeding with a full survey or making an offer, so you can discuss your budget etc and at the same time the surveyor may spot some issues which would put the project beyond your budget.

[BryanF]

baz do yourself a favour and get someone who has experience with damp/ old buildings to advise, they must understand RH/ condensation, damp/ weathering and so on