I have worked for a local council in UK for 15 years fitting windows/doors and have recently changed departments to fitting kitchens/bathrooms and general maintenance within properties-plastering/carpentry etc althou have no qualification certificates. Have looked at the list of skilled jobs required in Oz and gather certification is needed. Would this suffice? The list just says General Plumber? Cheers in advance!

I don’t think you have enough qualifications, but here is the skills assessment information for General Plumber. On the page is a link to VETASSESS which is the assessing body for that trade and they have a self-assessment tool for potential applicants to gauge their suitability for the assessment process.
http://www.immi.gov.au/asri/occupations/p/plumber-general-4431-11.htm

It’s very unlikely that any visa applications for plumbers will be processed for the next year or so anyway, so if you’re serious about coming here, perhaps you could look into upgrading your qualifications – I imagine that will be beneficial even if you end up staying in the UK. I suggest you join a couple of the expat forums where you’ll be able to get excellent advice on what’s required from people who’ve been through the process.
http://www.pomsinoz.com/
http://britishexpats.com/forum/forumdisplay.php?f=54

http://www.immi.gov.au/skilled/general-skilled-migration/pdf/migration-program.pdf Read this for info on visa processing priorities.