Ok lights 4,5 and 6 isnt an error code unless you have light 4 and 5 lit as light 6 will be flashing along with the row of lights at the bottom.
Also lights 4 and 5 isnt listed as an error code anyway.
But if you have lights 1,2 and 3 lit up this is error code F07 which is a heating related error code.
So if you are getting 1,2 and 3 then you need to pull the washer out and remove the back panel,
There you will see the heater at the back of the drum towards the bottom.
Check the wires on there are tight. If they are fine then you need to test the heater for resistance. It should read about 28Ohms. If faulty then the heater needs to be replaced.
But if the heater and wiring are both fine then the control board at the back is the fault and will need to be replaced and programmed up. Now pricewise for you to do this yourself then it isnt worth the repair as it will cost more then the washer is worth as you need to also buy the card reader and smart card to program the board up.
But Hotpoint do a fixed price repair for £110 all in and they will replace the board and program it up with there laptop.
So if you have them lights lit check the heater and see what you find and let me know.