Heater detailing

[rolesyboy]

Hi. Just received my heater case back from the powder coaters. Now need to rebuild it but I have a couple of things I need to source. Black sealant around body (would ordinary black household silicone do the trick?) , the screws i have aren't too good and the foam draft excluder stuff. Can any of you kind souls tell me where I can get these things as my imagination stretches as far as B&Q and e bay. Any other tips on improving the heater would be appreciated. Cheers. Mark