How to ruin a miniature with anti-shine

Yesterday morning, almost as soon as the postie had delivered the Army Painter Quickshade, I slapped some onto an alien miniature. Despite being a really basic paintjob (flesh painted a bone colour, carapaces painted purple and that was it) the Quickshade picked out all the details perfectly. Even the non-painting nerds started showing a bit of interest, as the results were so impressive!

I love the effect. Nice deep highlights, the almost "cartoon-y" look but plenty of super-fine detail makes the paint job look far better than it is. So this morning, after waiting the recommended 24 hours to allow the varnish to fully dry, I applied a quick coat of Army Painter anti-shine matt varnish.
The result wasn't quite what I was expecting:

All the lovely details have become a cloudy, grey gloopy mess! There's even a nasty crackling effect on the larger flat areas (like along the tail). Either there's something wrong with the spray varnish, or the way I applied it - my latex gloves were covered in sticky scales of congealed anti-shine varnish:

And on the metal minaitures, the effect was even worse! The matt varnish has managed to strip away parts of the quickshade varnish (in the photo below, you can see that on the solider's right leg  -on the left of the image- part of the underlying base coat is showing through)

What started out as an exciting new way of painting miniatures looks like a quick way of assigning them to the bin! I can't imagine that the plastic Tyranid alien is salvageable (paint strippers are likely to melt the plastic). Maybe some Mangers Paint and Varnish remover will restore the metal soliders as it did our Blood Bowl Orks a few years back. Or maybe, since discovering the sculpting inadequacies on these miniatures, I might just pop down to the local GW store and pick up some plastic soldier-looking miniatures?

After all, the plastic Tyranid alien looks great when painted up and shaded with Quickshade - the details really stand out far better than the details on these metal soldiers - I just need to find out how to finish them properly, without ruining them!