This is one of a set of 4 caches (3 micros and a small standard cache) that CAN be treated separately but were placed to take the seeker on a shortish circular walk (just under 2 miles)around an area of watermeadows known locally as Otterspool.
It is conveniently located close to Junction 5 on the M1. I suggest parking on a small road running alongside the main A41 close to the main gates to Munden House at N 51° 40.539 W 0° 22.664.
It's a 35mm film container, which can only take the very smallest of swaps. Please be very careful when searching for and replacing the cache. One slip and it's gone forever! (and you too possibly!)
If you are going on to attempt #4 in the series you should continue walking over the bridge when you will meet a small lane which will take to to the right spot.
Vg'f zntargvp - ybbx ng gur oevqtr! Cyrnfr ercynpr va gur fnzr cynpr nf lbh sbhaq vg.