"mad MAX" (aka Yokel-Motion 1.0)

So at £45-odd being the going rate for a Phil, I might end up getting 55t and 56t rings together with a 15t (I meant to write "...if I then get a 55t ring and 15t and 14t rear sprockets...")

One tooth difference at the front is hardly worth having on a TT bike, whereas having two different sprockets gives you two properly different gears. Phil sprockets are pretty expensive, but at least they are a rare example of UK pricing being reasonably aligned to US pricing, since they are $66 at AVT, so you don't have to feel like you've been screwed :-)