The UK rules actually do not permit any one to import items into the UK without a British plug, in the main what they do is have a load of adaptors so you can select the one for your country.
However 12 volt is common and you could buy a replacement power supply with UK plug on it.
It only requires two pin connection the double square shows it is double insulated and does not require and earth. The current is very low so a shaver adaptor would do the job but it may not hold it firm enough. There are other adaptors which have a socket shaped for the German plug which will hold the power supply firmer.
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