Thanks for all the advice from everyone about systems for carrying surfboards on a T2 pop top. After much deliberation we took our van to Campervan parts in Bideford www.campervanparts.uk/product-category/elevating-
roof-racks and the guys there fitted their system to our T2. It took a bit of tweaking to ensure that the bolt system used to attach the vehicle rails did not prevent the pop top from fully bedding down properly but some flush fitting hex headed bolts drilled through the pop top at strategic locations did the trick. We have found that with a longboard and a fish strapped to the
roof you can still elevate the
roof but it is a struggle and the existing gas struts are probably not sufficiently powerful to support the pop top with the added load - so probably best to take off the surfboards before raising the
roof. I guess it might be possible to obtain some new struts with a greater gas pressure that would be up to the task - something i might look into and would be interested to hear of others expereince with this. The other thing we have found is that with the boards up top the
roof flexes a little and it's a bit harder to lower the
roof and get both sides of the pop top to fully insert inside the
roof gutter. Overall its been a success and means we have much more space inside the van when travelling and the wind noise is not much greater tough there are a few more creaks from the
roof. I guess i need to surf on shorter lighter boards! A great advantage of the Campervan system is that you can move the cross rails on their mounts forward and backwards along the length of the vehicle very easily and take them off when they are not needed. I have posted some pics and i hope this info is useful for others who might be exploring
roof carrying systems. Its not cheap but the quality is good!