Get a decent insulated screwdriver with a good handle.
Turn off the main switch.
Tighten all the MCB and RCD screws, top and bottom. If any were loose, you have probably found your problem.
The screws should all be as tight as you can comfortably get them. Dont put undue pressure on the screws, they might shear the thread if they are a poor brand. But tight enough so they wont come undone on their own.
If the problem persists, then call the supplier as it may be a loose connection in the meter or head or main switch. YOU MUST NOT TOUCH THESE.
Edited because of concerns over the original content.
My fuse box is years old with the old style fuses etc. So i don't think i can do the above. Plus i wouldn't fancy trying it anyway!
Anyway update on my problem. I phoned the Electricty company, they wanted £35 to come out just to look at the meter and main fuse. However the guy didn't think my problem lay with the meter/main fuse. So an electrician is coming out tomorrow
In the mean time i have been searching the internet and i reckon i might know why all this started. My shower is a Triton 70si (7kw on a 30amp fuse)
Now a few weeks ago the shower fuse went,probably the 2/3rd time in 5 years. I replaced it and the shower was working again but then a week later no hot water. So maybe this last blown fuse has done something to my wiring?
I hope not by looking at the cost or rewiring a house!
What do people reckon the blown shower fuse has now affected the rest of the house?
Thanks again for all the replies