Thanks for all the tips & links folks.
I've pretty much decided to use a water hose to get some pressure to clear the drains out (rather than air).
Easier for me and it also provides an instant check that it's working.
As was pointed out in one of the links it's already soaking wet so a bit of spillage won't matter!
Also, now my (removable) carpet and mats are nearly dry I've decide to replace all the overmats (not the main heavy foam-backed carpet sections in the front) and maybe keep some as spares for winter (I have 2 sets which were actually on top of each other - a partial Audi OEM colour-matched set and a full dark rubber-backed set for winter).
Having rummaged on eBay I found these in Germany:
http://www.ebay.co.uk/itm/150734514481?
Now they're not suitable for me (I'd only want a PF S8 logo
) but what do we think - tacky or class?