Yes, as usual Dave is spot on in his article.
It may also be worth checking the fuse in the plug of the appliance being used. We have a 900w travel kettle which draws 3.9 amps and a matching 700w toaster drawing 3.04 amps, both have been fitted with 13 amp fuses rather than the required 5 amp suitable for the load. If either has a fault ideally users would prefer to replace a single appliance fuse rather than reset both the van and power source RCD which, as Dave points out, may also affect a neighbour.
Another handy note which may be worth labelling near to the habitation electrics:
6 amp = 1350w... 10 amp = 2250w.
Limiting yourself to these values will still leave a little in reserve giving peace of mind to the consumer.