This can be done on its own or whilst attempting the circular series Nan Clark's 6+1. It is very close to the suggested parking spot (also listed below) and you will pass by this cache at the beginning and end of the 6+1.
Nan was the licensee of the Three Crowns pub in the 1690s, closed in the 1890s and demolished in the 1930s (source: barnetfirst magazine - Nov/Dec 2007, published by London Borough of Barnet). Shame how all the good traditional pubs are disappearing.
The above link not only gives you details of the series but also tells of Nan Clark's demise and refers to her ghost who returns annually on 21st June - but has also been sighted in November, so could pounce at any time...
The cache is a 35mm film pod. Bring a pencil
*** Congratulations to Nicodaemus (author of the fiendish code-themed mystery caches which I am part way through) on First to Find 3 hours after publication ***