My rear wiper makes a very load clonking noise every time it gets to its parking position, any ideas?

Mine does this. I think it is because the spring to hold the blade close to the glass has corroded and not longer exerts enough force, hence the wiper arm hits the underside of the spoiler/light fitting thing

I looked at how much effort it would be to fix and decided I couldn't be bothered to remove the light fitting to get at it

Instead I treated the rear screen with a water repellent and don't use the wiper.... 2007 Zermatt Silver TDV8 Vogue SE - now sold but was a great car!

Quite often caused by the hinge in the wiper arm seizing up with crud thrown up from the road. Park the wiper so as it is pointing downwards and free up with the likes of WD40 clean and lubricate the joint with Lithium grease or such. Should solve your clunk unless the spring has indeed corroded away. Should've been old enough to know better...doh!
Current 2010 5.0 SC Autobiography
Previous 2006 TD6 Vogue SE
Previous 1998 P38 4.6 Vogue Autobiography 50 (No 10)

Wd40 applied and fixed, great advise thank you yet again from the learned collective

x  Should've been old enough to know better...doh!
Current 2010 5.0 SC Autobiography
Previous 2006 TD6 Vogue SE
Previous 1998 P38 4.6 Vogue Autobiography 50 (No 10)

Good one to know as it is the sort of thing that would drive me nuts
Glad it is sorted

Sorry to bump an old thread, but this has just started to happen to mine. Tried the WD40 but to no avail. Although the spring visually seems fine. Is it new wiper arm time?

A new wiper arm doesn't cost a lot, if the hinge is seizing up then i expect it looks scruffy with pealing paint and the spring has gone weak anyway.

Powerful do a kit for £50 with a new arm, blade and washer jet.

The rear wiper arm location is poorly positioned for washing and lubricating but perfect for the aesthetics of the FFRR. You need to remove the top rear spoiler (whatever they call it) to allow access to lubricate it properly and even when washing you need to switch the ignition off whilst the blade is in the six o'clock position. A FFRR PITA

Cheers, looks like something for me to do next week.