Nicholas49, these a/c may have opted (possibly at the request of ops) to divert en route before actually reaching Gatwick. Multiple possible reasons for this. Additionally, when several major airports are closed those remaining open may be limited to the number of diversions they can take (not necessarily because of ramp space but also ground handling constraints. There may also be considerable holding time before an approach can be made. If the route the a/c concerned were flying took them over or close to AMS/CDG, ops may have elected to avoid any problems by simply diverting to a suitable airport en-route.