Ok.
Buying anything in HK is going to be cheaper than UK simply because of VAT, unless Dixons is having a huge sale and dumping unwanted stocks.
If you’re looking for gaming or computer stuff, there are three places to look – the most famous is Golden Shopping Centre, accessible from Sham Shui Po MTR station on the Red line. Another is Wanchai Computer Centre, off Wanchai MTR station on the Blue line. And a third would be Silvercord, near Harbour City, probably closest to the Tsim Sha Tsui station on the Red line.
Or, you can walk around the Mongkok area, from Mong Kok station on the Red Line – most of the individual shops are in that area – but this also includes consumer electronics, cameras, and all sorts of other stuff.
As for coming to Thailand – let me know if you need any help. Can’t do the flight from the UK as it would be too expensive to book from here – but everything else you’re better off booking with me (again, simply by avoiding VAT to begin with).