tommy
I have just taken a look at the Ravenair website and it says £93/hour rather than the £66 that you quote.
If you are correct with the AVGAS for an hours flying costing about £42 I can't see how you could even break even with £22 to cover all the other running costs.
This leads me to the subject of small print, there are a lot of so called deals to be had on hour building and you have to know exactly what you are getting for your money, the difference between a Tacho Hour and a take off to touch down hour can be 15% and Hobbs time can add 20% to the cost.............. more if you fly from a busy airfield.
On the whole I think that £93/hour for a PA38 that is likely to be lacking in investment due to the (by this time) quickly aproaching airframe life is not a bad deal but I should just keep an eye on the "extras", the cost might go up a bit.