Yes sorry about the size of the manuals, I left them 'big' so they print well, the downside is their mostly 6Mb+ and take ages to download on slow connections.
As said the Carver Cascade is set to 70C on electric and around 65C on gas, this is HOT! so there could well be a problem if you can keep your hand under the tap for more than a second or two?.
Most likely is perhaps a heavy build up of limescale on and around the element, or a faulty thermostat.
Also, heavy electrical demands on site will lower the elements efficiency and therefore lengthen the time taken to fully heat the water
Normal times are about an hour from cold until 1997, after then with the bigger element fitted, about 45 minutes.