Hi Erica
Just come off the phone from Holland to the inventor of Kemdirect to ask him what was the answer to your question of how to remove the flies.
He said... that this warm weather is the problem but as the weather changes and becomes wetter and the surface of your caravan becomes wet you will have more joy of removing them. it is the protein from the flies which causes the problems as it is very sticky and during the very warm weather it sticks to the surface of your caravan.
Now, if you wish to try and remove them now, he suggests that you use a wet spong and put a nylon stocking over top and use his kemdirect shampoo...or try the one you are using at the moment.
You may need a lot of patience to remove them but it is possible.
If you then use Kemdirect Shampoo it will put a shiny solid surface onto your caravan and you will not have this problem in the future.
If you have no joy and want more information from him.. or us then go to his web site www.kemdirect.nl and send him an email and hopefully he wil be able to assist you further.
I hope this helps you and you manage to remove the little sew n sos !!!!
Joyce