I know we briefly touched upon the use of Groenpol heads in HK in the Groenpol thread, but I though I might expand on that a little.
With the help of GSV, I can try and illustrate what signal design is like there.
We'll start with the principles.
HK uses British design standard, primarily, which is a hold-over from British control. The principles are all there - primary and secondary signals, R&A together before green, 300mm symbols, box signs and exclusive pedestrian crossings. They also have a traffic signs manual based on the UK one, as well as the use of things such as mini-roundabouts and zebra crossings complete with beacons.
A few things are different, such as the use of flashing green men at pedestrian crossings in all locations, even junctions, which isn't done in the UK. They also use an amber 'T' instead of green in a standard head for trams, whereas we have a dedicated system for that - though they likely had LRT signals before we did as our first LRT signalling system was only installed in 1991. They also use yellow zebra markings on pedestrian crossings, though I believe this was implemented after the hand-over in 97. There are also all-12" heads found in some high-speed situations, though again I'm not sure if they've been installed after 97. Lastly, when backing boards are used, they're often oval not square, but I think this is because Groenpol's main backing boards are ovals for the NL market.
The signals.
HK used SGE signals painted in the B/W/B colour scheme up until the 80s, like the rest of the places using signals of this era, really. Also note the Bi-Lingual box signs. We had the same box signs over here, however obviously not bi-lingual. Most in the UK were modified around 1961 when our current signing system was brought in using a new sign symbol printed on a plastic sheet the size of the box, with the rest of it coloured in black. It seems the original style lasted on in Hong Kong until the actual signal heads were replaced.

05-546 by Nick DeWolf Photo Archive, on Flickr
After this period, they didn't use the Mellor head - though I'm not sure why. Instead they used other European standard signals, such as Swarco, Philips and Groenpol, though they still used Mellor style configurations, such as 300mm symbol aspects and box signs.
Here is a view of UK standards on Groenpol (left) and Swarco Futurit (Right).
Here is a close up of an LED-retrofitted Groenpol with NRT Box Sign.
Here's a similar setup to above, but with a right turn priority arrow on the right of the green light. This is actually still to the UK regs and is a common setup in London, though outside of London, the NLT sign would probably be mounted to the left of the green light, to form an upside down 'T'. It's interesting to note that there are no tunnel visors for secondary signals as there are in the UK.
Here's Swarco Futurit signals with the box signs mounted in their own housings just below the signal heads. This seems to be the most common method of signing with box signs in HK (this is similar to Ireland).
Here's an HK Pelican crossing, complete with Bi-Lingual UK push button. These seem to be very rare now, most having been replaced with the touch-sensitive button you can see on the other side of the road.
Here's a pic on Flickr I found of the UK PBUs

Hong Kong - How to use a traffic light by PixCat, on Flickr
Controllers.
I can't really tell much about the controllers, but looking around, I have found some British ones. This is a Plessey/Siemens Pelican Controller (I think, anyway!) and these appear to be PEEK controllers!
Bollards.
As a last note, HK uses these island bollards that are manufactured in HK I believe, but still follow the UK yellow bottom pannel/blue arrow combination. I found one British Haldo bollard whilst looking around, but it has a poorly hand-painted arrow on the front!
If anyone has anymore to add or if I'm mistaken with anything, please speak up!
