PPL vs NPPL
The training, in practice, is hardly different. By the time that you have completed the NPPL the only element for which you will have a shortfall for the issue of a JAR PPL will be that for Radio navigation. You may wish to include that element anyway.
Rather than undertaking the 100nm QXC required for the NPPL do the extra distance and satisfy the JAR 150 nm route. In practice this will require only an extra 20-30 minutes flying. Should you upgrade later then you will not have to do that flight again.
Most PPLs do not wish to fly aircraft of +2000kg nor carry more than three passengers. The other NPPL restrictions are;
No IMC, no night and must have an inflight visibility of 5km where as the UK JAR PPL requires 3km. Flight only within the UK, IOM and the Channel Islands. If all this is of no great matter to you then go for the NPPL and consider the PPL later when you will know better your position. It is hoped that when EASA gets it act together flight throughout Europe will be possible using the NPPL or whatever name they eventually choose to call it.
The Ishihara (my spelling) colour test is a poor indicator of colour difficiency. If it is important to you to resolve that issue it is possible to have a 'lantern' test which is more accurate. Telephone the CAA medical department who will help and advise on that.