Wouldn't you be able to trace the registered keeper off the V5 document as it shows the previous name and address, as traders usually don't put the v5 into their own name.
Anti freeze smells and tastes sweet. Check your coolant level buddy, unless you have a stash of chocolate hidden in your engine bay. Does the cabin smell sweet too?
If there is intermittent coolant bursts through the bleed valve then there is still air present. Only once the coolant flows freely should the air be free. Squeeze both the flow and return rad pipes repeatedly you should feel them becoming hot. Check coolant reservoir is full enough to the correct line too. Can take quite a while to free so don't worry.
If coolant has been released through the bleed valve it should be free of air. Close the valve and turn the heater on high and fast blower. When I have bled air locks previously I have the heater blower on low speed whilst I squeeze the rad pipes.
Hope you get this working ok.
As above agreed., The only issue that could arise is, should any panel having had new paint since manufacture, from an accident to a scratch repair, if the proper procedures have not taken place then this issue could arise.