If you really like the mid terrace then I would go for it. 2 toilets is plenty. We bought a 4 bedroom semi detached with one bathroom and no downstairs loo. We had that arrangement for 2 years while we saved up for an extension and a downstairs cloakroom. Not a deal breaker at all and as some people would say why are you worried about occasional guests? It would be your house.

Many houses like this have only one toilet and it’s downstairs. I think this arrangement is preferable. If guest come over for dinner they will have to use the one in the guest bedroom. On the two occasions a year when someone stays they will have to shower in your bathroom.

If you are feeling flush consider make the small toilet larger at the expense of the front bedroom. Or build an extension. But neither is necessary

A downstairs loo would be great if you can squeeze one in. What are the two structures in the courtyard?

Many thousands of houses throughout the UK have this layout and they all make it work.

It looks as though the original structure for the outside toilet at the rear is still intact, and if there isn't a toilet currently fitted, it could be sorted for peanuts. This gives a viable option for barbeques, and, potentially, dry summer visits.

While a downstairs loo would be convenient, many many people make it work with the layout you have!