Not sure if those are the right value. I bought a few off ebay though on the ferret finder page, Fitted a few now and they do work. Some times its worth cleaning that switch by take the yellow disc carefully off ( which is under there wheel )and use a cotton bud and some electrical cleaning fluid or some mentholated spirt might do it.
If you are getting a lot of interference its usually that switch.
http://www.ebay.co.uk/itm/Ferret-Finder-on-off-depth-switch-Deben-Terrier-Locator-/252130739923
On those it has B5K written on them which probably means 5K ohms = 5000 ohms I think,