How the UK handles taxes for seafarers

I have been doing some more research around the internet to find out more information on how the UK handles taxes for seafarers. One of the suggestions I got was to give up my Canadian residency as I hold dual citizenship with the UK. If you are thinking of this you may want to think again as it does have some implications for you here, but if you are then you may want to look at the following links.

http://www.hmrc.gov.uk/pdfs/ir20.htm
http://www.hmrc.gov.uk/bulletins/tb49.htm
http://www.resource.offshore.hsbc.com/public/offshore/p2g_pdfs/tax_facts/taxfacts_brochure.pdf