The issue of a concrete runway is more to do with rain water run off IIRC.
The caravans must just float away:
PLANNING APPLICATIONS CLEARED BETWEEN 01-JUL-08 AND 31-JUL-08 FOLLOWING
DETERMINATION BY THE DEVELOPMENT CONTROL COMMITTEE
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REFERENCE
06/07/0948/F
PARISH West Caister 3
PROPOSAL Re-development of site to form Motor Home, Caravan Sales and
Accessories with customer parking and offices
SITE Former CHC Scotia Heliport Base Yarmouth Road
West Caister Great Yarmouth, Norfolk
APPLICANT Beck's Motorhomes
DECISION
APPROVE------------------------ ---------------------------------------------------------------------------------------------------------