The Compukit 1 brochure states that the kit was being used by "hundreds of education institutions and individuals like yourself throughout the county." However, very few seem to have survived.
One was donated to the The National Museum of Computing (TNMOC) at Bletchley Park, England. Bletchley Park is known as the famous code-breaking center during WWII.
The third known Compukit 1 model is also in England at the ICL Computer Museum collection that was put together and is curated by Pete. I'm not sure how old the collection is but the website was first registered in 2006.
[Update: January 2023. As best I can tell, the ICL Museum seems to have added a second Compukit 1 to their collection. It looks to be a later version...the manual that is pictured looks more professional than the original manuals. (No insult intended, Ravi...I still like your original one best!]