So I have had a small amount of water loss for a good while and could never see anything. Today I found some drips so managed to trace where they were coming from. Turns out that the electric fan switch is weaping. Now should I just put some radseal in, I know some poeple don't like this. Or should I replace it, its not easy to get to. If I replace it, what's the process I need to go through to bleed the system as I know if it not done right on astra's the rad implodes.

Do not put rad weld in it.... doesnt mix too well with g12 coolant lol... its like a chemistry experiment gone wrong :(

Replace it and the seal. System should self bleed if you leave the expansion tank cap open during warm up.

Not much to add, other than to point you in the direction of the drain tap, which is by the bottom corner of the radiator. Pretty easy to get to once you're underneath. 'Two wheels on the pavement service ramp' should do you if you're skinny!