Ok just rang up mechanic and he said yep the rattling sound and why it goes away in 5 to 10 secs is because theres no oil pressure at the start then once theres oil pressure the hydrolic chain tensioned tensions up the chain, there fore the noise goes away.
Also, hes unsure (over the phone) why it doesn't start easily. He suggested putting some injector cleaner in to the fuel because they may be blocked up. Or taking it to a place where they can scan/talk to my computer to see what error codes its bringing up.