Thanks for your help. I couldn't extract the dipstick from the side as my transmission is an HBW 50 and there wasn't a whole lot of room to fish
around. However, I must have pushed it back towards the dipstick hole as I was able to, after many tries, retrieve it through there with a magnet. Fishing
around with a magnet from the side also allowed me to clean out a lot of metal shavings from the mangled dipstick.