Leaking brake fluid had never in my experience caused noisy brakes. More likely to be worn out shoes or possibly they just need a good clean out and lubrication of the relevent parts with the correct lubricant.

You need to strip them down and have a good look and then decide what parts (if any) you actually need.

That will then determine how long the job will take.

Normally when shoes become contaminated with fluid it acts as a lubricant, so if anything they should be quieter...as you sail on by..:-)

...pop your head underneath, if a cyl is leaking enough to wet the shoes then there will probably be a tell tale stain around the bottom of the back plate.

Not a big job to remove and inspect anyway, i'd be inclined to use a known mechanic for this and not subject yourself to a fast fit centre...there are good well run fast fit centres to be fair, and ORB, a regular poster, appears to have the services of one.

I'd estimate an hour should see the job done, shoes and cyls, but thats assuming everything goes well, on a 14 year old system though problems will crop up, corrosion being just one so it may well take longer.