Any question answered...

Right, I need a compact cranks, a very compact cranks.

the standard is 50/34, but I like to be able to have a 30t inner that are readily available, especially with a 48t big ring.

A lots of the compact cranks I see doesn't look it can go lower than 34t in the inside.

Have you looked for something dedicated to cyclocross? There were Rotor cranks on eBay for £125 the other day and you can get 40/25T chainrings.