Foxymoron, Chances are that you do have a Combi boiler.
It is quite common for Combi boilers to produce " milky " hot water.
The reason being a combination of the water being heated up very quickly, and a difference in pressure from entering the combi to coming out again.
If you do not need the temperature as high as it is now, turn down the temperature control, this may stop the hot water coming out milky. But, in any case , as you stated, the water will clear in a few seconds.