Hello Jeremy, and welcome to the forum. The former Coastal Forces Veterans Association (CFVA) newsletters contain articles on RMLs, RML 512 for one, and I seem to recall an article about a rescued American aircrew, which I will endeavour to find, although there were, unsurprisingly, a number of such rescues performed in the North Sea, given the large number of airfields in East Anglia from which USAAF bombers flew on missions over northern Germany, taking a flight path over Holland. Crews sometimes ditched on their way out after developing problems, as well as on the way home, having sustained damage from flak or night-fighters. I'll try and get them all scanned over the next week and post them online with a link here. Even if I don't find anything specifically related to 514, they should provide you with an insight into the work your father did.
I'll contact you by email later if I may about the photos in your possession.