Could this be a flood risk? Pic attached

[EluneBePraised]

DH and I viewed a house yesterday, needs a bit of work but it ticks many boxes for us. However, I was unsure about the back, immediately outside the building. The ground comes right up to the back wall with no sign of a drainage system anywhere and I'm unsure if this may be an issue in some way, such as a flood risk if it rains heavily enough.

My DSis has a similar thing at her house however the ground slopes away slightly from the building plus there are two small drains less than a metre from the back wall.

This house we viewed has neither of those, could we be asking for trouble with this? If I'm being stupid or worrying too much, feel free to say so!

Where would the flooding come from, does the garden slope upwards to a hillside?
Is there a way for the water to flow into the neighbours garden?
Is there a drain under the bins or do the neighbours have a drain?

The house is situated on a bit of a slope but its more evident at the front of the house. The back is a bit more levelled out but tiered - you go up a small set of stairs to the garden's grassed area (that's the retaining walls you can see on the left of the pic). This bit immediately at the back door is on more level ground. No drains that I immediately spotted during the viewing

What is the metal plate at the bottom of the stairs?
If the wall between NDN is solid the water will be limited to the patch shown and will have to drain via a ground level drain.
You can do a calculation on the capacity of the pipe to take water volume.
Where do the gutters empty to on your side of the wall?
Where do these drains start from / flow to and are they on a slope where flashflooding would force water to exit out of the drain into your property?

It's not a metal plate but a darker concrete slab.
Not sure re how the drains run but I currently live in a house a mile away with a steeper slope and the drains run downwards to the main sewer AFAIK. The houses were built at the same time so might be a similar set-up?
The gutter drains out at the side of the building (semi) and the ground there slopes down via the driveway to the pavement.

The drainage design will be adjusted for the site conditions.
If there is only 1 drains running from the side of the house you need to check if the area slopes away from the back of the house eg to the retaining wall and then down towards the drain and out to the street.
Otherwise you basicly have a bathtub filling with water and the only escape is when the volume of water reaches the drain for the down pipe. And dont forget that the down pipe is pushing an equal or larger volume of water off the roof into the same drain.