This is a British Seagull Forty Plus MkII manufactured in September 1970, making it almost exactly 50 years old at the time of writing.
Unfortunately I don't know too much about the history of this specific Seagull - but given that I live in Australia, and bought it in Australia, I think it fair to assume it was an Australian delivery from new, back in 1970.
At the moment - I know it has no spark, but experience tells me that just giving the points a clean and/or checking the spark plug cable should get it sparking again.
As with every restoration, the question is "How should I approach it?" - make it a complete, back to new restoration? Or just get it running, service it and leave it showing its history? Or perhaps something in between. With this one I am tempted to go with tidying it up quite a bit, servicing it, new spark plug, new gaskets, gearbox oil etc, and the one thing I always like to do, make sure the water chambers are clean, painted with anti-rust paint and the cooling system is working really well, but leaving it showing its scars - like leaving the Petrol Tank as it is, with the Australian distributors sticker attached - maybe just giving the tank a polish to brighten it up, but leave it like it is. I also see that the throttle level is broken, I'll have to get a replacement for that - it is too hard to use as it is.