Connecting Boiler Spur

Well I have gone and purchased a switch spur for my normal central heating boiler i.e. with controller and wall thermostat.
I have opened up the old normal switch connected to the boiler and find the following wires:
Blue from boiler connected to another blue using connector block.
Red from boiler connected to another red using connector block.
Yellow & green from boiler connected using a connectot block to black going to another socket.
Yellow & green with red sleeving over it from boiler connected using a connector block to an earth cable with red sleeving over it.
Black from boiler going to one side of the old switch.
Yellow (not from the boiler) going to tthe other side of the old switch.

Inside the new spur I have 2 earths, live in, live out, neutral in and neutral out.

How do I connect all these together?
Any help greatly appreciated.

where do the 'other' wires come from?

How was it wired before?

What kind of cable comes from the boiler? I'm a bit concerned about g+y being sleeved red!

The other wires go up into the ceiling, my boiler is in the garage, I can only guess that the wires come from the controller etc.
cable from boiler looks like normal flex

You need to find out where they come from and what they do - you can't proceed on the basis of guesswork.

You particularly need to sort out what's going on with those oversleeved G/Y cores. If they are earths then they should not be oversleeved, and if they are not earths then you need to rewire so that G/Y cores are not used for whatever it is they are doing.

Some photographs would be invaluable here.

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Hope this helps

nope, not a bit, can't see what connects where, or what the other ends of the cable are connected to...
you need to rewire those conections with the proper multicore cable and not use an earth as a live..