Just in case your still waiting for a Kew lookup.
I live too far from London to travel there just to visit Kew and the cost of either the rail or air fare and possible overnight stay makes using a researcher a cost effective alternative. Obviously one has to "research the researchers" to avoid getting a large bill for little or no return.
First of all to find out more details on Coastguard records at the National Archives have a look at the web site at http://www.nationalarchivs.gov.uk
[look at - red menu bar - select Research, education & online exhibitions Research guides > Records Research guides > Coastguard].
The National Archives web site has a list of researchers. From the home page at http://www.nationalarchives.gov.uk/default.htm
- red menu bar - select Research, education & online exhibitions > Paying for research. As well as details of using the NA's staff to carry out research [extract his record] there's a list of Independent Researchers.
From the groups select Researchers for: Coastguard and also noting the research guides reference to military records and the Admiralty it may also be useful to look at researchers for Military and Naval records. From the lists take the trouble scroll through them all and look at any with web sites and/or contact any with email addresses to check costs before requesting a service. At least one researcher has fixed price packages and several agree limits to costs. Ask for names of previous customers and/or testimonials and [copies accepted] beware extras like travel costs - see where they are based. For the record I am not a researcher nor do I have any links with any.