This is my very first post so please be bear with me! After searching wiki I can't find the specific answer I was looking for and being an electrical novice, I think it's prudent to ask for advice.
We've owned a 1990 Autosleeper Trident for a few of weeks (and already love it). We camped at a site for the first time last weekend 8 and found the leisure battery discharged after a couple of hours

I've consulted the autosleeper wiring diagram which shows connection from the vehicle ignition (via relay to 20A blade fuse) and from the vehicle battery (via another relay to a 30A blade fuse).
Both fuses are wired up to the positive terminal of the leisure battery, which is fine, but these wires then connect to 2 red wires that lead off to the ignition and vehicle battery under the passenger seat. So, there's no way of working out which fuse I'm connecting to which circuit (if you know what I mean?).
I just need to know I'm not going to cause any issues if the connections are reversed (50/50 guess at the moment). Is it detrimental to have a 20A fuse on the vehicle battery circuit rather than the 30A one or vice versa?
Many thanks in advance,
njamo2000....