I can braze up the hole if you want BUT: it will fuck the chrome, rechroming will cost a bomb.
Just get some UPOL body filler from an auto paint store. Bog it up and paint the bog with a chrome hobby paint
Enjoying it thoroughly… any more suggestions?
Serious answer: too much work. Anything you do is probably going to require having the fork rechromed.
Edit: beaten by everybody.
Is this for the Merckx Pista?
what Blakey said. he’s an engineer so knows about metals and stuff.
YESB RAKE
Good advice.
Or, do this if you absolutely, positively must de-hole
Sorted
Run a bolt (possibly a seat-post bolt) through the hole? Easy, cheap solution. Won’t damage the fork. Might not be completely flat but it’ll match the chrome in colour.
just buy a new chrome fork
AFC International Pty Ltd - An Australian family owned company - QuikSteel Epoxy Putty
Touch up over filled hole with silver/chrome paint?
Stick this over the hole:
Failing that, sticky tape some al-foil over it.
Accept the hole. It won’t change the way it rides and it is what it is.
Thanks everyone for their suggestions 
Management-speak party foul.
Embrace the hole. It makes your bike lighter.
there is no hole.
Go to your local metal fab company and ask for a long weight.
A Long weight won’t be any good here, what you need is a hammerfour
Left handed screwdriver might help? someone grab me the sparks for my welder!
need to check your indicator fluid if you drive to get the fork fixed as well.