Travelling in J and have an 8.5 hour connection time in DXB on my way to the UK. I Arrive in Dubai circa 6am so planning on showering and having breakfast in the lounge prior to leaving the airport for a few hours. British passport holder and hoping to have bags chcked all the way through to my final destination.

1) How long before my afternoon flight do I need to arrive back at DXB?
2) Is there a smoking area in the lounge?
3) Is there a facility in the Business Class Lounge to leave baggage safely and securely? Would rather not have my carry-on with me while wandering around Dubai. I know there's a facility at arrivals but I recall having to pay for that.

Thanks