All RAF SAR Flts are normally on-unit sleeping watches unless something prevents it such as redecorating etc! Last time I was there Culdrose and Prestwick were similar albeit perhaps at the nearby messes. The CG are a little more relaxed, where at some locations off base sleeping is permitted assuming it is close enough to permit flight prep and launch within the 45 min. Portland of course does not hold a night time standby.
Cheers