The only limit is Captains can't be captains after 60. A CAA/ICAO limit I believe.
Is that some SAR specific rule I have never heard of, or are you confusing it with the fact that a Captain aged 60 or over cannot fly with a co-pilot who is also 60 or over - i.e. ONE of the crew (Captain OR co-pilot) must be under 60
(I spent many hours flying as co-pilot on the North sea with Captains who were between 60 and 64 years 364 days old........)