If you make a change to an old property (that currently does not meet the current Building Regulations) then the new changes must conform to the current Regulations, wherever possible.
With the changes you propose, the most likely area of required conformance is to current electrical standards about distances between electrical switch sockets and water.
Since you will have to use a registered electrician to undertake the electrical work (because all electrical work in kitchens requires this) I suggest that ask him about specific layouts - I can only give you a general answer here without seeing exactly what you are wanting to do.
Gas is not normally a problem (apart from using a registered gas fitter for the work).
Before anyone picks me up on it, there are some situations where you cannot bring an old house to current standards. For example, change a gas CH boiler and you have a fit a condensing one, but you clearly cannot bring the whole of the house up to current thermal standards, as if the whole house was new build.