Blowing N/S reverse light bulb

[sidibear]

2008 B7 2.0TDI Avant S-Line
Seems to be a constant thing, every few weeks it goes, yesterday changed the bulb again and it blew the second time I selected reverse.
Can't seem to see anything wrong with the wiring upon visual inspection.
Bulbs are from Halfords if that makes a difference.

Any ideas?

 

[NHN]

Pull the lense out & check for any corrosion, water etc mate.

 

[sidibear]

Have done, nothing, no signs of water ingress or corrosion, the bulb holder is clean and unmarked.

You can have a scan Friday afternoon.

 

[sidibear]

Solved it.
Chatted with the Audi guys last week at the meet and they suggested a bad earth caused by corrosion on the terminal. Had chance this weekend to have a good look at it.
Apparently, it seems, after you have previously changed the bulb if you push the plug on fully until it clicks you don't get the bulb fault on the dash and the reverse light works.