looking to change plans after planning permisson is approved

Dear poster, The council do not require planning permission again if you choose not to build the particular part of the approved application. You will be ok if you decide to just go for the double story if all passes. Just make sure you fill out the right description when you submit to building control as they charge on the size of the project so if you are not doing the ground floor annex then the building control fees will be cheaper for you by building only the double. I hope this helps....

Your best bet is contacting the council and posing the question. At a guess I'd say it'd be classed as a minor amendment as it's a reduction in size of the structure.

To do this officially would require a material adjustment on your application if passed (free to submit within 1st year-not essential). If its still within the council's workings and you're yet to get a response then update them with an email and revised drawings as this could help especially if the side extension is visible from the principal elevation. However, building less isn't frowned upon from a planning perspective should you be granted approval on your current application. As long as the building facade now being exposed is being built in the correct manner ie with a cavity then meeting regs won't be an issue. Consequently, you might pay less for regs should your squared meterage drop you down a threshold. Hope this helps, Best of luck.