Logitech MK540 Wireless Keyboard and Mouse Combo

I already use and have been very happy with my current Logitech wireless keyboard and mouse, the Logitech MK270. However, after extended daily use one of the supporting legs is failing and so it is time to replace and maybe upgrade it. The MK540 is considerably larger than the older model and feels like a distinct upgrade in build quality, but then it is more than twice the price. The keyboard set arrived presented in an upmarket product box of the sort expected from a well-known company like Logitech. In the box were a K540 keyboard, M310 mouse, USB key and a warranty leaflet. AA batteries were preinstalled in both items. To my surprise, there was no User Guide as such although none is really needed as all you have to do is plug the thing in and turn it on. Unlike the others, I have used this is a full-sized keyboard and has a traditional desktop deep key travel feel. If you are accustomed to laptop type keyboards this may not be for use as it is quite noisy in use and requires old style heavy keystrokes. It has all the usual keys in UK format and includes the Windows key and a short set of non-standard keys at the top for email, browser, audio volume etc. There is an easy to find Off/On switch on the top right to reduce battery drain and lightweight dual-position kickstand supports on the back. The mouse is pretty much standard, large sized, three-button design with a centre scroll wheel. Both the keyboard and mouse works instantly once the USB key was inserted and the...