Making downstairs toilet into a bathroom

[Kentlane]

Hi, we are looking to buy this house but would need to convert the downstairs to have a shower. We were thinking possibly of knocking down the internal wall and expanding the toilet so the bathroom continued into the porch.

Has anyone done this? Think its viable with a budget of £20k? As the porch is an extension the wall is probably structural so would increase costs I think?

Any thoughts appreciated as we've never done any work to a house beyond painting.

You could just have a separate shower in the porch or have a walk way where the window currently is.

@RandomMess thanks we hadn't thought about the window becoming a walk way. That's definitely worth exploring.