Police were called to reports of an assault in a building on Lyndon Road on July 31.
A man in his 60s was taken to hospital with face and torso injuries.
The injuries are not life threatening or changing, and he has since been discharged.
A man in his 40s was then arrested this week on Wednesday (August 6) on suspicion of actual bodily harm.
The suspect has been bailed while further enquiries continue.
Police also want to speak with another man, aged in his 50s, about the incident.
A Met Police spokesperson said: “On Thursday, 31 July, officers and the London Ambulance Service responded to reports of an assault at an address in Lyndon Road, Belvedere.
“A man aged in his 60s had sustained injuries to the face and torso, and was taken to hospital for treatment.
“His condition was assessed as non-life-changing and non-life-threatening, and he has since been discharged.
“A man in his 40s was arrested on Wednesday, 6 August on suspicion of actual bodily harm, and has been bailed pending further enquiries.
“Police are keen to speak with another man, aged in his 50s, in connection with the incident.”
