A friend of mine recently installed new Kitchen worktops and kitchen sink for us. It's not his normal line of work but he's pretty handy and did a good job on his own kitchen. He's done us a good job but left us to seal the gaps between the worktops and the walls which is fine. I then subsequently asked him if he had sealed the sink itself - which he hadn't. I was a bit concerned about this but he said to just go round it with transparent silicone sealant without trimming the nozzle off and go round it with your little finger. I am not sure this will do a very good job - at the very least I'm thinking that if I try and push the sink up a little bit from underneath it might give me more of a gap to get into - at the moment it fits nice and snugly so there is virtually no gap to get into, but of course water will get in there no problem. It's a sink with a lip overhang. Thanks in advance for any advice.