Reckon that there might be a tobacco connection.
Whitehaven used to be a major trading port during sailing days.
Many ships from the American Eastern seabord used to land there as their first port of call.
Cargoes (e.g. Virginian tobacco) were then decanted on to smaller boats operating the coastal trade.
One of their destinations was Belfast (where e.g. the leaf tobacco was teased in to usable form).
http://www.thepeerage.com/p547.htmFamily originally form Nottinghamshire, but were then given a connection with Anglesey in Wales.
http://www.ngw.nl/catalogue/tobaccocards/countryseats.htmEntry 90 for Earl of Annesley in one of Player's tobacco card series.
Also note entry 2 for LASCELLES famly, Earls Harewood - big players in the Carribean, cousins of Royalty.
[One of their lesser, but more honorable, members ended up in the South of Co. Down.]
http://www.libraryireland.com/UlsterDirectory1910/Castlewellan.phpWhiteside, William, landsteward for Earl of Annesley
Greer, G., sub-agent, Annesley office
[Their names might figure in the land deeds.
Available via LDS microfilms.
Leases were often for three lives - often grandfather, father & son are mentioned.]