I recently put a fence and didn't quite think it through properly. I
used a 75mm post for a gate supports and it really should have been
bigger (you live you learn). Although it won't fall down it does have a
slight wobble at the top when closing the gate. I am considering
methods for strengthening the gate without replacing the post (which
the wife will go nuts about as she's been waiting for the fence for a
while).

I was considering either putting another post against the gate post or
using a bit of metal angle iron or similar and strengthen that way.

I was hoping someone may have an idea as to what would be best and
where I would go to get the metal if thats the best way.

Any others ideas would be appreciated.