Hi Alfie,
Yes its possible that the rain is driving up under the profile and in the absence of proprietary "bungs" (Eaves fillers) it might be an idea to add a facia board under the profile. The board can be cut up (or scribed) to the underside of the profile and the samml gap between top of facia and underside of profile can be filled with sealant. Faining that, a small amount of expanding foam can be used to fill each peak between the profile and the wallplate. Here is a link to some expandng foam. https://www.diydoctor.org.uk/DIY-superst ... 00-ml.html
