Owning your own home

The next step will be planning permission. Due to my design, essentially a four storey rectangular box (I had do build up due to the size restrictions of 40sqm) Im concerned that the planner wont like it because it will obviously be fairly different from the other 70's council houses that is sits amongst.

There aren't really any problems stemming from out of character in developments among 70's council houses. They aren't something that is considered something worth preserving in terms of consistency in the area. Provided the design of the building isn't something that would be considered an eyesore then there shouldn't be a problem on these grounds. Your main issue is on affecting other people's sunlight. Casting a shadow that significantly blocks another person's sunlight can cause a lot of issues in planning.