Hi Liam,
Welcome to LZ and the madness that is P38 ownership.
If I were you I would take this out of the "Introduce Yourself" section and ask the relevant questions in the Range Rover section.
Many people have overhauled their EAS system as a DIY job and avoided the Main-Stealer or other Garage robbery.
Ask people like @Doo about EAS or just do a bit of searching on here.
If you convert it to coils you will be taking a backward step and missing out on a lot of comfort and road feel of the P38 I think.
Until you get stuck in, you won't know what the problems with the EAS are.
It might have sprung an easily fixable leak, need a new bag or two or have a duff compressor.
Everything is fixable. Good luck mate!