I discovered a small leak from the rear window seal , the leak appeared on both bottom corners when it had rained.After some research and a chat with a friend I purchased - wait for it some Captain Tolley’s Creeping Crack Cure from Amazon , I applied it using a small hypodermic needle as per instructions and bobs your uncle no more leak
Captain Tolley’s Creeping Crack… https://www.amazon.co.uk/dp/B00JQ6XHWC?ref=ppx_pop_mob_ap_share