i will have a 400w light running through a digital ballast
a water pump
the filter/fan
1 maybe 2 clip on fans and probably something else i have overlooked....

Thats a lot of plugs is it safe to run all these plugs off a normal extension lead from a double wall socket? or should i buy a surge protecting extension lead? will that help or do any good at all?

i want to be able to sleep at night and know the house wont burn down

not ideal really but i've run my gr and a veg room off a extension lead now for 3+ yrs, 1 ex lead runs the flower room with my fans (cf, osc etc) straight in and a surge protector in to the ex lead, then all the other plugs inc contactor in to the surge protector another lead plugged into that one, to the veg room,

one day i will be able to find a sparky who i can trust to wire me up a proper board

hope that makes sense, just got up to watch the F1 and had my first spliff

You might need to find out how many Amps that extension lead can take, You need a fair amount to be safe. Do you have a contactor?

thats fine with what you are running imo

e2a five year on more then that and no problem safety still here not burnt to a crisp-now reaches to touch wood

To get a rough guess you need ohms law to start. If that is too much at first, you will need to figure out the ampere rating of each piece of equipment (both the stuff that draws power and the stuff that delivers it. Add together the stuff that draws power and ideally your total is about 80% of what would be the maximum that any power supply component (outlets, extension cords, your breaker) can handle.

Since you have two sockets to plug into (but they are probably one circuit), put your light on one and every thing else on the other. A multi outlet power strip with a breaker on it is nice but not essential.

Do figure which breaker circuit in your breaker box you are pulling from. Figure what it's load capacity is. Do buy a smoke alarm and get a fire extinguisher and have it handy.

But also, realistically speaking, what you are running is very small potatoes. I wouldn't worry about it. But do get a contactor, or at least a very heavy duty outdoor timer for your ballast.

I am getting a extinguisher and a smoke alarm for up there
whats a contractor? and an outdoor timer for my ballast?
cant i just get some surge protecing plugs and extensions and have them from the wall socket to the grow? i know feck all about electric tbf

You shud really use a contactor (Magnetic Switch) and timer to bring the contactor on.
Using extensions isnt Ideal, but if you put them after the contactor in the circuit you will be safer than just using extensions.
If you use a timer and no contactor, the timer 9out of 10 times it melts on, so that the light is on constant, unless you paid for a good timer that is.

If you have no clue about electrics you could try doing some reading up on it. But I would keep your lighting equipment and other things to a minamal untill you figure out how the electrics work better, and feel more confident in what you are doing

Maxiswitch 4-Way Light Controller (13A), a contactor is used to plug your light and timer in to so it doesn't blow your timer and very possibly start a fire.
very important piece of growing equipment if your using any thing above 250w iirc
DONT grow without one m8, really not worth it