Invicta wrote:
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 inside
the house is located after a small rectangular header tank and before
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 suggestions as to
1) Where the water supply should come into the house.

Well typically it's in or near the kitchen because the kitchen sink has
to be fed direct from the mains, not from stored water (and from the
description of your loft, you do have stored water). You can confirm
this arrangement by turning off the stopcock in the road and checking
that the cold tap in the kitchen is turned off immediately.

2) Wether there should be a StopCock before the header tank

If there was no stopcock in the road, then absolutely 100%, because
you'd have no way of turning off the mains in a flood. I'd still
consider it highly desirable to have one before the header tank - ie at
the point where the main enters the house - and if it was my house I'd
be fitting a stopcock tomorrow!

3) Best method for plumbing hot and cold water into our kitchen.

Whaddya mean, 'best': in what way?? Nothing inherently wrong with what
you've got providing you have mains water in the 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.

AFAICS so far the only real problem is that you can't find where the
water enters ther house - hard for anyone else to help with that. Have
you checked the nearest point of the house to the stopcock outside? Can
you detect the sound of water in pipework around the house when the
kitchen tap's running? Are there other houses around yours built at the
same time, where you could ask where their stopcock is? (Of course if
you can find the entry point in your house you might well find a
stopcock there!)

David