pace Robin B. and Ted W., I don't believe - despite the explanation in the notes - this can be speculatively narrowed down to prospectively prepaid or retrospectively accrued.

I am submitting this because a number of other answers and discussion entries are not answering your question, or answering it in the negative, when I think they are just saying "I would have done this differently".

So, to your question: "is Prepayments ok". My answer, yes absolutely fine. Why? -

1) Vorauszahlung is translated in the eIFRS glossary as prepayment, see my discussion entry as to why this is relevant;
2) prepayments and prepaid expenses are used interchangeably by a number of practitioners - see example sentence from IFRS clarification on long term prepayments for inventory supply contracts (i.e. prepayments are equated here to prepaid expenses to explain why they are not included in financial assets) and CIMA link below;
3) Oxford dictionary of accounting definition of prepayment: A payment made for goods or services before they are received;
4) Ted makes a good point about prepayments: "Care needs to be taken with "prepayments" so that it is clear whether they are prepayments made or prepayments received" - True, but your example is from the notes to the asset side of the balance sheet, so the context makes it obvious;
5) inconclusive point this - a number of large UK companies do not use "prepaid expenses" anywhere in their annual reports, but do use "prepayments" - eg Tesco and Sainsbury.

This is not to say that "prepaid expenses" is not a better answer, it probably is. Also, some caution is warranted as I do not understand RobinB's point that "You should avoid using "prepayments" here, because this is the term normally reserved for prepayments on assets, i.e. "geleistete Anzahlungen" in German GAAP." - this goes against my understanding (e.g. see points 1,2 and 3 above), but I could be wrong so it would be interesting to hear more on this. (Besides, even supposing RobinB is right here - and he usually is - his use of "normally" suggests that you could be justified in putting something else, he would just do it differently, which brings me back to my reasons for writing this answer...)