Thanks for the thanks guys!
OP - 8 weeks is the guide by which LA's try to abide, more of an aspiration really. As part of the 8 weeks they have to consult with neighbours etc which takes 3 of those 8 anyway so at the speed the LA works you can see where the 8 weeks goes.
Dependent on what you want to do, it may not require pp but may be permitted development - google it - there is a good gov website which tells you what is and what is not PD.
My understanding is you still need to apply to the LA for PD and they will ask your neighbours what they think and if anyone doesnt like it, it triggers the requirement for pp (I may be wrong)
Dont worry too much about objections - The LA dont really take much notice. If there is a reason for your plans to be knocked back, the council will identify it, they wont be caught with their trousers down by a neighbour coming up with something they hadnt. We had an objection - well more of a rant really - but there was history there. The objectors didnt want the original house built (in 2004) and it went to committee and they lost. I think they viewed it as another opportunity to whinge about the original house being built. I took a load of pictures to disprove what they were saying and went on a charm offensive with the planning officer who wasnt having any of their nonsense after that!
PP costs £172. As stated I did my own initial drawings - Took me a total of 12 hours - Yes they have to be good, but not that good - Just a clear respresentation of what it looks like now and what it will look like from all sides and roof. If other houses have the same this is a good prescedent.
If you get the drawings done you could probably get a deal whereby they do pp drawings and once approved, add the building regs stuff to those drawings for say £500-1000.
Once you have pp, you can either go full plans submission or building notice. Both cost the same, for me about £800. Full plans is you submit your building regs drawings and the council spend another 8 weeks looking at them and then say they meet regs or not. If you get them professionally done, its unlikely they would say they dont meet regs as most of the regs stuff is generic and the architect will know his/her stuff and they do it everyday. They thing then is that provided the plans are followed exactly you are pretty much sorted through to completion i.e. no nasty surprises like this doesnt comply, that doesnt comply etc.
Building notice - you submit and 48 hours later you can start without any plans. In reality though my LA asked for my plans and on seeing them then asked for structural package - all of which were supplied - The thinking is that with a building notice you crack on without plans and the inspector inspects and signs of each item as you go along so if you do something not according to regs they will require you to change it. The reality is though if you get a builder to do it, they will know exactly what is required for each stage as its bread and butter stuff for them so you are unlikely to not follow regs unless the person doing is a complete numpty or perhaps someone from overseas unfamiliar with they building regs.
I researched each component of building regs as I went along, looked at the plans and cracked on. Its common sense really. My inspections have all gone really well - Just got 2nd fix elecs now and completion.
I would go fixed price for the job with trades and get it in writing. I would try and get trades via word of mouth. I was quite lucky with the ones I had, all good lads. The only slight disappointment was the first brickie who did from footings to dpc - not the best job - got him from one of these trust a trader websites so didnt try those again.
Re your drawings try an architectual technician - They do the same as an architect but cheaper. Some of the architects firms will offer submission services for a fee however you dont need this - pp is just a simple application form with all the drawings attached - do some research and save some money, youll need it!
Good luck