It always suprises me how pushy aircraft can be after their has been an incident at an airfield. Controller workload is almost trebled at times of incident even when it appears there is no immediate talking on the RT. Therfore after an incident ATC have to wait for replenishment of crash CAT and of course there is the issue of controller breaks before they are fit to undertake their job again not to mention internal investigation to into what happened.
Yes Cambridge has grass runways available, but if there is no crash CAT they can not be used. Therefore the number of runways at the airfield is not relevant.
Controllers dont like to refuse traffic, after all they are doing the job to provide a service. Most I know prefer to be busy rather than not. However, it would be nice for aircraft to work with Air Traffic control, and not get upset or pushy when they are told something is not available. Dont forget, Controllers have to look at the whole picture, where as some pilots seem to be only aware of their immediate environment.