correction it's RMB not HK$you can get a 5 day shenzhen visa on the 3rd floor upstairs, in a set of doors at the official visa issuingh place) after passing the barriers ( not the cts office pass the barriers within lo wu station or the next to the stairs in a hole in a wall cost HK$460 there, also takes around an hour or so) cost HK$307 on a uk passport, i was there when my mate had his done in 15 minutes during early march this year.
on the other hand , the issuing office in wan chai will take 4-5 days for a full visa to anywhere in china and cost HK$300 for a single and i think HK$550 for a double on a uk passport