As a start for my new build I am planning the garage/workshop which will be completed first (to wait for the bats to leave the bungalow we are demolishing!!!). It is to be 11 mtrs by 7 mtrs with a low pitch metal roof but the architect wants 190mm solid walls which I feel is over the top. They brought this down to 140mm hollow block but want 450mm pillars every 3mtrs. My last garage was 100mm walls with 200mm pillars every 3 mtrs and 190 gable walls. Where can I get info on wall construction for garages for building regs?

Does the door take up a complete end wall?

Reducing the size of the door so you get some corners may allow weaker walls. However at 7m by 11m you are getting hit by the lack of cross basing from internal walls.

In Scotland, over 30m2 needs building warrant approval. I don't think you're this side of the border Joe but we have the small buildings guide attached to the building regs and if you comply with the requirements then you cover the structural requirements of the regs.
It applies to garages with an unrestrained wall height up to 3m from memory so might give you some pointers:

http://www.scotland.gov.uk/Topics/Built-Environment/Building/Building-standards/publications/pubtech/techsbsg/

Ring TDC and ask to speak to Mick Maguire he's Very helpfull.

3 times the footprint of my house

Put the pillars on the outside?