Robbie,
I think you are quite confused regarding the NPPL license.
First of all, all the info you need on the NPPL is
HERE, a simple google would have got you that.
4000 on a FS wont count for anything other than give you some idea what instruments are for, there is no feedback or stimulation like flying a plane for real.
Do you NEED to fly a PA28, if you are constrained by a budget then look at the microlight scene, some fast,efficient stuff out there at the moment, you did say all you were going to do was bimble around the SE of the country so it would fit the bill.
You will get a student pack when beginning your training, you should not need much more than that to obtain your license.
Jon
www.RuskeyAirfield.com