Does anyone have any experience doing something like this ? The site in question isn't in a row of houses or anything like that, so keen for any thoughts/tips/experience 

 

Many thanks in advance 

How much more do you want to raise the current approval by?

1 hour ago, DevilDamo said:

How much more do you want to raise the current approval by?

It's for a commercial building. Another 0.5m to 1m. There was a previous planning approval that was higher and approved (now lapsed), which I'm thinking should strengthen the case..

It does not seem a huge increase, so you can only try.