Swapped the hooked front sprocket for a new one and the chain makes a *lot* less noise now! Still was a bugger of a job trying to get the rear axle back through the wheel and took multiple attemps 
Also changed the oil and filter, found I had insufficient oil in the 5l container, so had to buy some more, then discovered that somehow I'd overfilled it, so had to drain some out and refill until the level was right!
Also changed the oil and filter, found I had insufficient oil in the 5l container, so had to buy some more, then discovered that somehow I'd overfilled it, so had to drain some out and refill until the level was right!