I suppose one could construct a very tenuous argument about section 7.3, since this references quality in addition to safety, but given that these are clauses with the "X" mark and clearly aimed at temperature controlled services it seems to be a very big stretch.N
Nonetheless you may be able to circumvent this by discussing with the customer for whom you are storing the chocolates?
Presumably they understand that you're an ambient store, and are aware of the services you can/can't provide. so a statement from them confirming that their products are not adversely affected by ambient summer temperatures in the UK could negate the need to do anything further.
Obviously there is a slight danger that this isn't something about which they'd given any previous though, and thus a can of chocolate worms may be opened, but personally I'd prefer to do that than to find out it's a problem after it has caused some sort of expensive issue for someone.
Again given the scope of the facilities you can offer, it may simply be a quick study to map the warmer/cooler areas on hot days and preferentially allocate storage in the latter to the chocolates, but only if really necessary.
Hopefully your service contract also references the fact that your service is ambient and not temperature-controlled, but it might be worth checking just in case