The Prince Alfred's Guard Museum, located in Central Port Elizabeth's Prospect Road, was formed through the amalgamation of a Military Museum formerly housed in the Donkin Reserve Complex, and the Regimental Museum of the Prince Alfred's Guard Regiment.
In 1856, the Prince Alfred's Guard, a City Regiment, was formed as the Port Elizabeth Volunteer Rifle Corps. The name of the Regiment changed in 1860, after providing protection to Prince Alfred, Duke of Edinburgh, Queen Victoria's second son, while on a visit to Port Elizabeth. The Prince Alfred's Guard Museum is housed in an old Victorian style Drill Hall, and is one of the finest examples of architecture from its period. 
The Hall was opened in 1880, and has served as the Regiment's Headquarters ever since. The Old Drill Hall which has been declared as a National Monument, has undergone extensive restoration, and has been partly used as a Museum since 1996. 
 
Geolocation
-33° 57' 50.4", 25° 36' 39.6"
References

https://www.wheretostay.co.za/topic/3522-the-prince-alfreds-guard-museum

Further Reading
 
https://www.sahistory.org.za/franco/historical-conservation-nationalist.html
https://www.sahistory.org.za/.../prince-alfred-ernest-albert-16-second-son- queen-victoria-after-whom-several-places-and-t
https://www.sahistory.org.za/.../prince-alfred-house-waterloo-road-wynberg