I think the fundamental point you have overlooked is the ratio of professionals to volunteers.
Special Constables and Volunteer Firefighters certainly contribute to their respective services but are dwarfed in number by their professional colleagues.
The RNLI operates 233 stations with more than 4,800 crew, 300 lifeguards and numerous shore helpers all of whom facilitated the rescue of 7,507 people and the assistance of 9,041 others in 2004 alone.
http://www.rnli.org.uk/
btw MCA/HM Coastguard have a staff of 1,165 supported by over 3,250 volunteer Auxiliary Coastguards.