I was looking at a "Model PL09564 PLUG-IN POWER MONITOR" on the web and printed out the product manual (one page), which I happened to have in my jacket pocket when I was browsing in Maplin later that day and came across the same product labelled "Model 2000MU-UK PLUG-IN POWER MONITOR", which I bought.
The two products' sheets are the same except for such substitutions as
Congratulations on your purchase, and welcome to Prodigit 2000M Plug-in power monitor.
Congratulations on your purchase, and welcome to PL09564 Plug-in power monitor.
and the captions under the figures ("Figure 1 2000M Front Panel"; "Figure 1 PL09564 Front Panel"). Both of them even have the same "Funcion [sic] Configuration Table".
However, the one from Maplin is rated for "Altitude up to 2000m", whereas the other is rater for "Altitude up to PL09564".