Hi,
Just so you are aware the proxy sensors are only used to action the steering direction change and are not used once the steering direction change has completed (the 45 degree one is used for carousel but that is seperate). Most likley a passing seal on the rear cylinder. The UK services team can be emailed uk.services..combilift.com, just replace the 2 dots in the middle with the at sign and they will be able to help you. Combilift also has lots of technical information on the web site and knowledgebase that is available to dealers.