Hello Graham,
The easy one first, AS PR suggests the normal household cleaners are usually quite satisfactory. After all the materials and finishes we see in caravans are essentially the same as those at home.
As for toilet rolls, we use a normal low cost domestic soft tissue type. All rolls these days have to be bio degradable, its just that some take a bit longer to breakdown than others.
Now your point where there's no definitive right or wrong answer. It depends on what risk you are prepared to take.
Theft from caravan sites is still thankfully very low, and I (and most caravanners on this forum know) know many caravanning friends who have never had a theft of any of their property. So the chances are that if you don't secure belongings, then 9 times out of 10 nothing will happen. But times are changing, and it does seem that theft may be on the increase, so it is probably wise to secure your belongings, and not to leave temptations.
There is another consideration. If you were to have someone thieve an item of equipment it would certainly spoil your holiday, and may prevent you from using your caravan, but also if you haven't taken reasonable precautions to prevent theft, then your insurance is likely to be invalid.
