batteries the right way around  or led light leads to the correct end of the batteries?

 Seen these flounder lights in the shops...
Sort of takes me back to the old school days.
 A broom handle. Drill the end and tap a 10" nail with head cut off into the hole
 A small galls marmite jar with little hole drilled into the lid.
 A torch light bulb either soldered to  light electrical wire, or if bit more fancy, a old torch bulb holder soldered on. The old Dolphin torches where best sized bulbs.

Bulb (holder) in the jar, wire thru the lid with a grommet and heap heavy grease or gasket sealer.
Around the lid to strap to the broom stick some old fashioned  rubberized insulation tape.
 And run the wire up the broom stick to one of those large square Dolphin torch batteries kept in the side pocket of your jacket.
 For the flounder was a small size potato sack. about 1/4 to 1/3 from the top, a bit twine threaded thru side to side.
This tied around you waste, and the top 1/4 or 1/3 was the 'flip top' for it.

Now we have to buy these expensive things...
Marmite now comes in plastic jars ..torches are near all led now, bulbs obsolete??

Just had a thought here, the old bulbs sent light out in all directions under the water... led lights are directional..maybe an issue ???

Or just jumped into the little dinghy..someone pushes gently from the stern and you sit up the bow with the spear light in the water.

At 82 years of age I have been there done all of what you say.

Yes as above I purchased one off Tas-Tackle (RIP) and it had two probes that had to be immersed in water to create the circuit and switch on the LED's, it works fine, I must brush the cobwebs off it... as I love Flounder spearing...

terrafish wrote: Try giving the two little probes on the top of the light housing a bit of a scuff back to shiny metal. One of mine had a problem once, and that sorted it.

It will be like my old trailer lights...contacts on the bulbs USED to need a quick sand ...
They have not been cleaned for a few yrs now. Last time I cleaned the contacts then a quick spray of lanocoate...put covers on  good to go.
And they are permanently in the weather, elcheapo plastic incandescent.