DIYbanter - Water Pipes in 1970s House

This is my first post so it it's in the wrong section please re direct me. We have just moved into this 3 deroom semi and have started to replace the kitchen units. When I came to knock down a partition wall (between kitchen and dining room) I found half of it was built with plywood instead of plasterboard. I then found two felixible plastic pipes (supplying hot and cold water to the dishwasher and sink) comming down through the ceiling from under the floor boards in the back bedroom. The main StopCock for the house is under a small metal inspection plate in the public path in front of the house. The only one I can find in located after a small rectangular header tank and fefore the large round water tank in the loft. This tank has a ball cock in it . I can't find where water comes into the house or a stopcock before the header tank. Has anyone any sugestions as to
1) Where the water supply should come into the house.
2) Wether there should be a StopCock before the header tank
3) Best method for plumbing hot and cold into our kitchen.
I've worked on previous houses and the feed has been either in the kitchen or under the stairs with an easily accessible StopCock so I'm baffled with the current system.
Any advcie would be very much appreciated. Kind regards, Bernard.