I am traveling from the UK and want to layover in China can I get a Visa on arrival

VOA is almost impossible unless you have very urgent thing to handle in China.

For your situation, you plan to make a layover in China and then fly out of China? If so, probably, you can book flights to enjoy the 72-hour free transit. Under that policy, the VOA is not needed. If you want to leave the airport, you can only apply for a stay permit in the airport to leave.