The Turbo Electric head shown in the eBay listing won't work with this particular cleaner unfortunately. It's actually intended for use with later Numatics that have the 24 volt power take off system, identifiable by a "figure 8" style socket on the front of the motor unit.
Models with the red socket on the back use a 240 volt power head, something Numatic no longer offers. However, it would be easy to source a suitable head elsewhere. I'm thinking perhaps a Filter Queen power nozzle could be rigged with an adaptor to fit the Henry 32mm tubes, and rewired with the appropriate length of cable and a plug to fit this machine.
A Vorwerk power nozzle could probably be made to work as well. If you search eBay Germany there are adaptors available which convert Vorwerk fittings to accommodate standard round tubes. After a little creative (but safe, please) wiring, you'd have a great power head that would match your green Henry quite nicely. Vorwerk bits and pieces are as common as dirt in Germany, and therefore tend to be rather cheap even with postage.