Apparently Size Does Matter!

Recently I thought I had an issue with something loose or detached at the bottom of the engine adjacent to the OSF wheel.

During the winter months I try and use my Karcher under chassis cleaner (UCC) as much as possible to clear out muck and salt from under the vehicle.  However, at the location mentioned above the UCC was hitting something that was blocking it from moving freely, even at its lowest setting.  I had a quick look, but couldn't see anything obvious.  The vehice has had a service and a MoT since then and nothing untoward was mentioned.  Last week I used the UCC with no issues, and was able to move freely.  The only difference I can think of is during winter I have my 16" steel wheels on, and in the summer I have my 17" alloys on.

This has me pondering what is the component my UCC is hitting and is it pertinent to the Scout?  If not, would I be hitting this item if I had an Octavia fitted with smaller wheels?

Many thanks,

Fin