programmer first 2 are n & l, e is a block at bottom but programmer is double insulated
I meant with the seven wires shown not the timer terms which you clearly marked L+ N
It looks like instead of using 4core flex they have used the cable earth as a conductor.
By the E symbol next to some of your wires it confuses the drawing as I do not think they are all being used as earth.
This may be same with some of the wires marked N,may not all be neutrals
By the drawing i gave you and with your one i think you could work it out.
The ch on,is to the stat and stat output on to possibly the valve
hw on and hw off, will be both at the cyl stat or one, , may be near the valve,the valve also needs a N+E
One of these Hw on may possibly also link to the boiler and maybe the pump either at the timer or at the other end, as per drawing, these also need a N+E from somewhere
Not too sure about the frost stat
could be wired somehow to over ride the room stat but not sure
There should be a N+E as well to the stat
And a L+N+E to the timer/programmer.
Although it is DI you still need it to join to the g/y wires IF any are earth
It is just the non standard colours they have used are misleading.
If you redraw the s plan drawing using the coloured cores you have.
Work out what is neutral to the stat , pump, boiler and valve, then you wont have many wires to work out.
And genuine earths if any
Do not assume though that
g/y is earth
or
Blue is Neut
as i do not think it is
The earth wire incidentally should not be used as anything but earth,
If you find it is
Apart from rewiring in 4 core cable, you can not alter this, so you should mark with brown tape to warn people
sorry