Well, some time last year I ordered a ProSport water gauge to add to my collection, and managed to order the one without a peak/hold feature. As I wanted them to all be the same, I intended on selling it, but forgot to.
For my recent birthday my girlfriend ordered me the correct gauge, only in Fahrenheit, whereas my oil temp one is metric. 
So I now have for sale two gauges, as below.
This one is in Fahrenheit, is identical to the one below and I’m looking for something like £40 plus postage.
http://prosportgauges.com/amber-white-premium-water-temperature.aspx
Or this is the one I ended up buying which was the one I originally wanted:
http://www.rspec.co.uk/index.php?main_page=product_info&cPath=3_84&products_id=349
This one is not peak/hold, is in Celsius and looks mostly the same. I’m looking for £30 plus postage.
http://www.rspec.co.uk/index.php?main_page=product_info&products_id=329
Both are brand new and boxed with all the original parts - they were never fitted. Sadly sending the more expensive one back isn’t an option as my girlfriend got it from the US, and shipping to the US and then back again is as much as the gauge, it’s cheaper to just buy another one and sell this one at a loss.