Sorry only replying to been crazy busy. I've read over your steps
Step 1 no problem, I've been able to work out which cable it to which end and fitting into the switch I can do no problem.
Step 2 a little confused.
''Switch live brown, you mean the brown for the fan? Any idea looking which one this might be or is best I turn power off disconnect and try it.
Definitely turn power off
Basically what you have going to the fan is just a switch live and neutral and you need a permanent live for a timer fan
The brown is currently the switch live you have 2 options, either:
Just make the black perm live or to correct the wiring colours to brown perm live and black switch live (needs 1 more step).
On your pic of the back of the switch you see you have 6 terminals total, 2 rows of 3
Along the top row you have L1,L3,L2 with a link wire between L1 and L3 - this gives it away as a perm live
So you can either:
simple route - put the black into either L1 or L3 doesn't matter as they are linked anyway which ever is easier to fit the wire into - then black at the fan is your perm live
or to correct the colours so it makes more sense in future or for the next person who looks at it you need to do 1 more step
Trace the brown to find out which terminal out of the 6 that the brown wire from fan is going into - i cant see from the pic - it will be the brown wire from the same cable as the loose black and the grey which goes into the connector block with the blues
Once you have found which terminal the brown is going into then take it out and put the loose black wire into the terminal you have just taken the brown from
Then put the brown you have just taken out into either L1 or L3
This will correct the colours at the fan