What AlKo specify as the hitch limit is irrelevant. It's what the caravan manufacturer states what the limit is on the weight plate that counts. It may be the same, but it could be less.
However it is a guideline so probably not enforceable in legislation. I am unsure whether the figures on a sticker on the side of a caravan could be enforce as again they are only a guideline and I don't thi nk the sticker is mandatory otherwise they could never upgrade the MTPLM of a caravan?
However as usual we are getting way off tangent from the original post. The outfit is legal there is no doubt about that, but the issue is whether it is safe or not. In my opinion which doesn't count for much, it is not a safe combination especially as the OP wants to start touring around Europe again.
The OP has been given the correct advice in a number of posts regarding changing either the car or the caravan. It is not their decision.