Having gone through the same process as you tedwest96 I got my Class 2 then Class 1 a couple of years later and to be honest is wished I just went and got my Class 1 straight away. Sadly when I went and had my Class 1 it was found I was slightly colour deficient and unable to fly commercially (ended up with a restricted class 1 though). So If you have any issues about your health just go and get the Class 1 straight away to avoid any disappointment.
The only pain about the Class 1 is getting to Gatwick to have it, I had to fly down which was another £100 on top on the £350 for the medical.