I attended a memorial service at Christ Church Cathedral in 1983 for the men who died in the Graf Spee episode, some of whom are buried in the cemetery. Strangely enough the ship I was serving on was HMS Achilles. I remember seeing the rusting hull of the SS Great Britain as well and in contrast the burnt and buckled superstructure of the Sir Galahad.
Hope this link helps.
Falkland Islands Info Portal - History Articles