I got the wheel off the ground with a trolley jack like alx's photo thanks, I added a couple of ratchet straps to the roof just as a precaution.
Your all correct in saying there was a tight spot, I think it was mentioned once or twice but more of concern was the the cause of the tight spot which became more apparent.
The anoying click noise was definately from the chain and was due to a single link on the chain siezing up and not letting the chain return completely straight after going round the sprockets, also the cause of a tighter than normal tight spot. Measuring on this tight spot gave a wide range between loose spot and tight spot so as the chain went round it was flopping all over, I saw it flopping around while running in mid air on the trolley jack and a strong wooden fence beam across the suspension link to 2 axel stands as well as ratchet straps to the roof , didn't want it falling off now did I.
Order and waiting on an DID o ring chain £70 inc. p&p to arrive and decent riveter tool £40 inc. p&p.
As far as I can tell the sprockets appear to be ok. I hope I've done the right thing in just replacing the chain and not gone for the sprokets and chain together!