it used to be a callback item on berlingo's, you will have "cups" on the top of them, it was poopereon idea of fixing the problem they knew about
they say you should replace them in pairs ( as the other side will be weaker and wear quicker )
mine cost me about 150 quid to replace the 1 side, it would have been 250 for the pair, but as the van is crap, i took the chance
you can buy the tool and the spring, but be carefull, as they need to be compressed alot on the berlingo