[Mike SX]

UK 2009 i30 CRDi Estate, 38k. I have read other posts about ESP problems post coupler replacement, but none experienced today.
Today it took me just 4 hours to remove the column (with wheel locked in straight ahead position and not removing from spline but removing bottom UJ bolt instead) and reinstall. Battery disconnected (waited 20 minutes to avoid air bag explosion etc).
Battery reconnected and engine started. ESP light was on, turned wheel fully left then fully right, shut engine down and restart, ESP light off. Wife helped, but only holding column in reinstall position. Part  from Amazon cost £3.99 Inc P&P. Hyundai main dealer (Colchester Essex UK) quoted £972.22 to replace complete column, refused to replace only coupler.
Incidentally, the ESP switch is not latch type, but simple push to change from ESP on or off with each press.
Q.E.D.

[Surferdude]

Interesting approach by the Hy dealer. 🤬  
Dob him in.

In Australia the coupler replacement is readily done by most decent sized independent workshops. 300 to 400 $AU. So, a couple of hundred English £.

[Surferdude]

Good job by the way. 👍