It is certainly unusual though not rare for fall towards house, but given the marginal distance 50mm between paved level and DPC I would be concerned of potential damp breaches to DPC through excess run-off and/or heavy rain and wind driving run-off/splash towards house.
Certainly the designer needs to resolve potential hazard to retain integrity of DPC, it may necessitate the installation of acco drains to safely remove surface run-off and avoid any potential build up of damp at wall areas.
Depending on how paved area is jointed eg silicate sanded joints would alleviate any potential moisture build up at DPC, whereas sand cement joints although more robust provides no escape route for run-off, which is why in your case the direction of run-off towards building would be a cause for concern.