This is a polite notice to make you aware that you are parking on the pavement. You are obstructing the pavement. A member of the public has complained as there is not enough access for pedestrians and especially wheelchair users. Where you are a member of staff at Hampton House or a member of the public, it is in your interest to move the car as soon as possible and not to park here again, otherwise you will be fined either by a Traffic Warden or Security.
All this, because "a member of the public has complained"? One person? Why should the wants and needs of one person outweigh the needs of the many who need somewhere by their hospital or place of work? And look, there's plenty enough room for someone on foot to squeeze by.
we're also going to pick up on the "fined by Security". It's a public pavement. BRI security have no right to fine anyone for parking on public pavement. Private pavement, maybe. But not the public highway -or the designated parking areas alongside