Low pressure and temperature

Hi, I moved into my flat last month and have struggled with my Pulsacoil A-Class ever since. I am a shift worker so am quite often getting up at 4.15am for a shower. It takes about 15 minutes for the temperature to get to a level which is just about warm enough to allow me to shower. Also the pressure is so low it takes twice as long to shower as what I used to take in my old flat.
I have set the timer to turn on 2 hours prior to my alarm clock going off to allow the water to heat up. I have several switches all over the airing cupboard and in the 2 bathrooms but neither increases the pressure or the temperature. It is impossible to have a bath as the temperature just doesnt get high enough, even during the day or the evening, and it would probably take 2 hours to fill the bath due to the low pressure....no exaggeration.
If anyone has any suggestions I would be so greatful as I really cant afford to get a plumber or boiler engineer out due to just moving.
The boiler has a sticker on it which states it provides high pressure hot water but I am struggling to believe this. Also there is a leaflet (no instructions) which states that I should get "power shower pressure" and that when the water is turned on it will start out very hot to sterilise the pipes then reduce to about 55 degrees c. This is not happening with mine. The water is lukewarm at best and then takes forever to heat up. Even with the temperature gauge at full and after 15 minutes of letting the water run it is still only just above warm.
Please please can someone assist me???

Sound like the plate heat exchanger is scaled up.
How old is the unit?
Is the cold water pressure ok in the rest of the house?
If not check that the stop cock is on full.
And also ask neighbours if theirs is ok.
If you look in the book page 6 number 11 on the picture you have a Y type strainer/ flow regulator valve fitted.
It is possible this could be blocked.
As always with these matters, there is always a choice of possibles.
Mike