My boiler is displaying at L1 code and i have not hot water or heating. Is this something i can fix myself.?

google it, you'll find the manual, it explains the code, low flow overheat. It also instructs on what you need to do.

I think the pressure is too low. Read the gauge on the boiler. If it's less than 1.0 bar the boiler needs re-pressurising. There should be a braided filling loop near or just under the boiler. Slowly open the valves at each end whilst watching the gauge, When the gauge indicates 1.5 bar close both valves. It should start working normally. If not it's a job for a heating engineer. Try Checkatrade in your area.

Whats brand model number? Is it steam or Hot water boiler?