Vacuumlover, I thought maybe not - it was such a long time ago when it all became a requirement for sleeved pins. With the style of plug you have on your cleaner, it is possible for anyone who unplugs it to touch the pins as it is unplugged. This isn't quite the probelm when it is plugged into a standard UK wall socket, but smaller surface mounted sockets do exist, as do of course adaptors and extention leads. One has to take great care when plugging and unplugging into these as the pins of the plug sit much closer to the edges of the socket area, thus can be touched much more easily.
With sleeved pins, only the insulated section would even be exposed if the remainder was sufficiently deep enough into the socket for the pins to still be live.
Another problem it solved - when UK appliances were not supplied with plugs, it was not uncommon (though highly dangerous) to find people were using the appliance by wrapping the bear wires around the pins of a plug attached to something else, and plugging in. The reasons for this were two-fold; either through laziness / an inibility to fit a plug, or because in days gone by when homes had more than one style of plug & socket an portable appliance was needed to be used in several different locations, thus one plug would not fit in all sockets. We really don't know how lucky we are with our wiring standards compared to how it was only a matter of years ago!