Jaguar Forums - Jaguar Enthusiasts Forum - What is this "drain" on my flintstones car?

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Its currently plugged in and I'm wondering if it should be and where it leads to and whether I should open it up and have a hose connected and through the wheel liner.

Normally I'd leave it alone as is but car had the toeboard patched over and over again, multiple times, rotted plates sandwiched together so the wheel liner was definitely out multiple times, the wing itself hasn't got a speck of rust on it so I'm wondering if this used to be open in the past and whether its the reason so many of these wings rust.

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I had to change the front brake pads and while there I stupidly thought I'd poke at the rusty corner that was bodge patched multiple times in the past by the previous owners. By the time I cut it all out, quarter of the drinker side floor was missing, 30cm of lower sill, half the toeboard and most of the inner sill in that corner. That's two days of DIY work, right there. Just about to go and underseal it and put it back together.
The captains side technically doesn't have any holes but its equally as bad, multiple sandwiched rotten plates in places, think I counted 4 in a few spots. The car has no rust whatsoever from the sill up. Still wondering if I should spend two more weekends fixing it or pass it to another "enthusiast". With no ramp and car on axle stands its more than hard work, you weld from meter away with one hand and half blind to a poor thin metal half the time, hence the "lovely" looking welding!
Its structurally sound now though and will be good for another 20 or 30 years. Off to underseal it and put it back together.