Having persisted in trying to find what was the cause of U483 and U1301 sinking in Deadlight, in the designated Airforce position. I eventually came across a Polish site, which once the translater had done its best, these two boats are mentioned, as being sunk by Mosquito and Liberator, on checking the aircraft in service with the Squadron's involved in Deadlight [RAF Squadrons by Wing Commander C.G.Jefford], then RAF 224 [Liberator] and RAF 248 [Mosquito] were the squadrons. Meaning, as mentioned gun fire could quite feasably been used to sink them. John