the brown sludge would be the batteries, they will be toast. depending which way up it was stored the electronics may work after a clean. If any of your club members have a light canon yo can borrow it's easy to mix and match to see what is still working
HTH
Simon A
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I've just had a quick look on the web and
the store that shall not be named are selling the electronics for £66 and the batteries for £90 so if everything else works you can rebuild it for far less than a new one.
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