Seamus, having been one of those soldiers who couldn't solder for sh-one-T, the solution is:
-low temp solder (which I could throw in with the kit for free)
-fine sandpaper ( to remove the oxide layer) and most importantly
-flux fluid(Carrs Green is a good one)
Once you have these, it is easier than glueing, seriously. It is next to impossible without these items.
Alternatively, I could look at presoldering some of the elements for a few quid extra, leaving some easy glueing and painting to the customer.
But I do suggest trying the solder...