How many 5 days visa can I get? Ie can I enter China stay 5 days leave and then enter again tge nect

The experience and the practice of issuing Shenzhen VOAs shows that this particular VOA is issued at most twice a month. It is hard to say if you would be granted a Shenzhen VOA immediately after you have exited Shenzhen. If you plan to do that, you are advised to stay in Hong Kong or Macau for at least two overnights so that your old Shenzhen VOA does not connects with the dates with new VOA. Also, since you are obviously UK citizen, you have to be aware that the price for a Shenzhen VOA for UK citizens is relatively steep 834 CNY based on reciprocity.