Sid, you need a fairly deep socket to accommodate the screw or you could try going a shorter screw. Forget about pliers. A stubby ratchet or driver is best.
It's a pretty uncomfortable job, tweaking your arm and shoulder into that crawlspace. Felt like I was impregnating a cow,.. (artificially of course
You can make it a lot easier by raising the hull and sitting it on its side. Such as on sawhorses against a wall.
I had to remove the cleat, just to replace the starboard map pocket.
So if you need to replace those too, this would be the time to do it.