What is confusing me is that they replied with 'pass your message' while they have the required information from the previous controller. Do they just want know what my intentions are although they can derive it from the flight plan I would think....
Very often, they won't have sight of the flight plan. In my experience, it would be unusual for a controller who already had your details from a previous unit to respond with a "pass your message". In response to "pass your message" after an introductory call, it seems perfectly reasonable to give full details. If the controller simply says "radar contact" (more usual outside the UK) or confirms identification and the type of service, then it seems reasonable to leave it at that, and the controller will prompt for further info if required.
In the UK, as well as the terminology "contact" vs "freecall", a change to a different (non-7000) squawk immediately before a frequency change is a good indication that some coordination has been carried out.