No Hot water first thing in a morning?

Hi, I have a Glow-worm Swiftflow 80. We have had one of the valuves changed as water was coming out of pipe outside of house. Pressure kept dropping and having spoken to a neighbour who has been told the boiler is on its way out so to just keep topping it up and another plumber telling me we have a leak, I switched off the central heating in case there was a leak on the radiators and topped the system back up. The pressure hasn't since dropped, however first thing in a morning (6.30am when I get up) I cannot get hot water upstairs and its hit and miss whether I can get it downstairs, however an hour later when my boyfriend uses the bathroom he has no problem obtaining hot water. Any advice as its really getting to me?

Demelza
May 2008