I went on a wander after my guitar lesson in Hither Green today to seek out the crazy golf place. I can confirm that it is open, and it's situated on the Meridian South complex near to the Tesco Metro.
Here it is in all its glory:
18 holes! It's £5 for adults and £3 for kids, and from what I remember it's open from 1pm - 9pm on weekdays, and 11am - 9pm on weekends.
Please do correct me if I'm wrong!