I'm finding conflicting opinion on whether it's OK to charge the battery with it still connected to the car.

I get the sense that the CTEK-type chargers are routinely used without disconnecting the battery, but I'm not sure about doing the same with a normal battery charger.

I have never bothered with disconnection in the past with previous vehicles but with all the electronics in the FFRR, and their propensity for going wrong, I decided it would be worth asking the question.

So, when using a normal battery charger, do I disconnect the battery or not? 2006MY 4.2 SC
BMW R1250 GSA Rallye TE
Triumph Tiger 1050 (sold)
1979 Pontiac Trans Am (sold)

I've always charged mine whilst still connected.

Of course, I may just have always been doing it wrong.....

If it is a "smart" charger ie. one that monitors the state of charge and adjust accordingly I would leave it connected. If not I would disconnect. John
2008 Stornoway Grey 3.6 Tdv8 Vogue
2005 TD6 Java Black Vogue - Written off!!
GAP iiD BT
2003 Discovery TD5 Auto, Nanocom Evolution - gone to a new home!
MasseyFerguson 152 - No electronics!! - Sold

There's no problem with leaving the battery connected and charging it. Best practice is to connect the positive lead to the battery and the negative to vehicle ground away from the battery to prevent sparking and possible ignition of hydrogen venting from the battery.
With a non-smart charger just make sure it's not left on in high current mode for a long time which can overheat the battery, that has no bearing on whether it's connected to the vehicle or not though.
CTEK chargers, if they have the option, it's best not to enter Recon modes with it connected to the vehicle. Recon mode outputs up to 16V and some electronics in the vehicle may not be happy with it.