This interests me, my grandfather served in the RN during WWII on HMS Hood, HMS Broke and then in Burma but was buried with his medals prior to my birth.
Could we get them back? And how?
I am pretty sure that the answer is no. The medal office will make an initial issue of medals which were not issued at the time, or subsequently, and they will also issue replacements (so marked) to recipients who can prove that their own medals have been stolen (a police crime number is usually required). Neither are the case in this instance, so your only course is to buy genuine examples of his medals to represent his group, or good quality replicas which you can have named in the correct style. If you want to pursue this course of action, send me a PM and I will recommend a very reliable firm who will give you a quote. Whatever you do please do not buy original medals and have them renamed - that is a cardinal sin in the medal world where it is rightly regarded as vandalism.
When a chum of mine who was a very keen medal collector retired from the Parachute Regiment in the 70s he worked for a while for a local undertaker. While he was in that job they buried a local woman who was one of the very few female recipients of the Military Medal during the Great War. She too was buried with her medals, Bob saw them being placed in the coffin before it was screwed down. He confessed later that the tears in his eyes were less for the dear departed, than for the loss of a fine group of medals. I used to tease him that he ought to go along to the churchyard one night with a spade and "liberate" the medals - not that I am suggesting that you do the same!