Only a couple of hours after posting, Malcolm contacted me and came over like Flash. He investigated the scene, quickly found the causes and suggested a few solutions. For the small jobs such as replacing bath seal and adding sealant, he gave me a choice between the pro (hiring him) and the common (DIY) versions - either would go with his full explanation and instruction. I managed to DIY it within a day (well, not so confident with my skills so may upgrade to the pro version if mine does not work). Malcolm even had a quick look at my boiler and gave me some advices before leaving. Very happy with his prompt and reliable services. Highly recommend.