BTW - depending on whether it's an optical illusion from the photo or not, I'd be tempted to move the seatpost pack mounting up a tad (couple of cm should do it) to allow for it to bounce a bit on it's mounting without bashing your crudguard.
Already done and seat lowered slightly to make it more comfortable!
Proper test ride today - 50 miles out through Stisted, Great Bardfield, Great Dunmow, Pleshey & Littley Green - only two of those had beer stops:
1.5 x Old Newt at the Bell in Great Bardfield accompanied by a sausage & onion bagette, a very nice 4% beer
1 x Wibblers Apprentice at the Compasses was good too, 3.9%