WhiskyInTheJar

Hi everyone. I hope this is the right place to post this. I’m wondering if someone can help clear up a bit of confusion. We're considering buying this 1960s bungalow, but it's got a strange quirk going on with internal windows caused by a corridor running along the back of the house (see diagram). I'm trying to work out whether the red or yellow highlighted wall is holding the roof up (or a combination of both?). Our initial intention was to take down the internal wall/windows and extend the walls on either side to meet the outer (red highlighted) wall. That would make a little more bedroom space and lose the strange corridor feature. However, we've got the title plan, and it's got a dotted line where the red highlighted wall on the diagram is now, indicating that this might have only been an overhang/lean-to structure, which calls into question its strength to support the roof - I think? But, I see there's a large wooden fascia above the windows on the rear wall, so could that be covering an RSJ that's providing enough support to hold the roof up without the internal wall doing anything? I think it's worth noting that without the rear corridor, the roof would either end strangely high or be pitched irregularly and very steep at the rear of the house, so surely the outer wall is taking the weight? Can anyone advise based on what I've provided whether or not the outer or internal wall is likely to be load bearing? Grateful for any advice!!! You might be able to tell that I know very little! Thanks in advance!