What is the easiest/simplest waya to increase shower water pressure - have been told to move water tank so drop is bigger and/or get a Salamander pump (the latter I have been told is the best one on the market?)[size=18][/size]
The easiest solution by far is to fit a shower booster pump as you mention but of course you must have sufficient hot and cold water available to ensure the shower will work correctly.
Unless the law has changed, requiring showers to be run via a tank, the simplest and by far the most effective thing would be to run it from the rising main. If it is run from a tank, then cold water presure is irrelevant except that it should cope with a pump emptying the tank PDQ. (Although what "good" might mean in connection with the pressure......)
It depends on the shower you have. You cannot connect directly to the mains cold water if the hot water is tank fed. If the hot is tank fed the cold MUST be too.