Rose do want a sunny spot, but the refracted heat (heat coming back, heat being reflected back off the wall) could be too much. Roses like water, but not on the foliage, excess water on the foliage will cause rust among other things.
Both the refracted heat and excess water would be abiotic (not associated with or derived from living organisms) plant problems that if not addressed open the door to biotic (associated with or derived from living organisms) problems.
- I would ensure that the wall is not generating excessive heat, if so cover it with shade cloth.
- Don't water the rose foliage, only the ground.
- Make sure the roses are getting the appropriate amount of water, the pictures make the area look like a damp. Roses don't want constantly damp soil. Cycle moist to almost dry then top moist again...
- Make sure there is air circulation for the roses.
- Make sure you giving the roses nutrients as appropriate for the season.
It also looks like the roses are sharing space with other plants, I don't think that is typical, most of the time roses are in beds pretty too themselves, or at least they get their needed space. It also looks like the soil is typically damp due to the watering needs of the other plants, having plants with different watering needs in the same space will result in some of the plants being unhappy.
Better pictures of the bed and soil would be most helpful, Often the issue with the plant is not due to the plant itself, but the environment it's in and were not seeing all of that, just the wall.