Thankfully, the 7D is weather sealed:

IMAGE LINK: https://flic.kr/p/psQF​aY
www.Loz.Pics Wethersealed by Trugga, on Flickr

This how it happened - this competitor added a little more right lock and floored it - thankfully I turned to move and only got a little mud on the camera - I got covered Only two little specs of mud on the front protector filter.

IMAGE LINK: https://flic.kr/p/psKA​p4
www.Loz.Pics IMG_2042 by Trugga, on Flickr

Suffice to say I did not change the lens in that state - continued to use it, but left it to dry out at home and this evening removed the crud with a dry toothbrush and then wiped it all over with a damp cloth. Looking much better now.

A good day out

Lawrence