Amending an existing rear extension that got planning approved

[stelio di bello]

Hello,

I am looking for your wise advise and your view on amending / doing a new planning permission...

Unfortunately I have changed in mind in regard my already built rear extension that got planning approved two years ago.

I have now decided that I would like to extend on the side my rear extension (as per drawing) and I was wondering for your opinion and your view in regard my chance of success on obtaining a new planning permission to extend the extension on the side 8m widthh * 3.5m length...

Do you think planning would accept me building 8mt on the side of the already developed extension or is it likely to request me to reduce the width of the side extension? As a backup plan in case the extension will be refused I could try my luck with an outbuilding and then hypotetically connect with a corridor to the house? Am I right thinking that I ABSOLUTELY need a new planning permission to change the layout of the extension already agreed and that 4-8m won't be seen as a minor amendment?

What are your thougts and reccomendation about it? Shall I just try my luck and put in the application or what would suggest? Architect is saying that I got 60% chance of success but I would like to get an other opinion and forecast on the chance of success....

Cheers