Nope there is no link wire from 2-4 the blue core out of 2 is traveling under the number 4 terminal that's allOk mapped out your terminals
1 = switch live to boiler / cyl stat call
2 = neutral
3 = earth
4 = pump live from boiler
5 = ch on from programmer/ room stat com
6 = as above
7 = HW on from programmer / Cly stat common
8 = HW off from programmer / cyl sat satisfied
9 = CH call from room stat
There is no permanent live in the wiring centre
Matt
Looks like a link wire from 2 - 4 N to L in that case.
The still too many wires in 5 if we count them from the right to left.
In terminal 5 you have 3 wires
ch on from programmer, the room stat connection at the top and a link wire from 5 to 6 at the bottom ( which does nowt )
Matt