Of the twenty-six Spitfire PR.XIII conversions, seventeen were from Mk VBs which had their cannon deleted leaving four machine guns. W3112 was an ex-MkVA, L1004, X4615, X4660 were Mk VAs that had been converted from Mk IAs, P7505 was a Mk VB that had been converted from a Mk IIA, R7308, R7335 were PR.XII/Type G converted from MK VAs, X4021, X4766 were PR.XII/Type G converted from MK VAs that had been converted from MK IAs.
According to Wojtek Matusiak 'A' wing conversions retained the full eight gun armament. Dr. Alfred Price states that the armament of the PR.XIII was reduced to four machines guns in the outer positions. If he is correct then this can only apply to the 'A' wing conversions. Spitfire 70, Flypast Special states that some early conversions retained all eight machine-guns.
AD354 was the first PR.XIII into service reaching Benson on 21st April 1943. 541 and 542 Squadrons were the first operators of the PR.XIII but they were mainly used for training until the summer of 1944. Apart from that they were used for low altitude photography of the French coastline prior to D-Day. From December 1943 onwards 4 and 400 (Canadian) Squadrons used them for pilot conversion from Mustangs to Spitfire PR.XIs.
In 1944 eleven PR.XIIIs were handed over to the FAA. In February and March these were used at Lee-on-Solent and Henstridge by 808 and 886 Squadrons for training in PR and gunfire spotting duties. At least of some them went to 761 Squadron, AKA No.2 Naval Air Fighter School, at Henstridge, where they were used between March and June 1944. Six were used from June 1944 at Henstridge by 718 Squadron which underwent several re-namings – Army Co-operation Training Unit, from October 1944 Army Co-operation Naval Operational Training Unit, from April 1945 School of Naval Air Reconnaissance and finally after relocating to Ballyhalbert No.4 Naval Air Fighter School. It was there that the FAA career of the PR.XIII came to an end in October 1945.
The PR.XIII was declared obsolete by the RAF in early 1945. The RAF discarded specialised low altitude PR Spitfire variants about the time of D-Day replacing them with fighters modified to carry photographic equipment and given the significant role designator FR (Fighter-Reconnaissance).
I have seen no mention of any PR.XIIIs being used in Malta. By the time the PR.XIII came into service in 1943 the Siege of Malta had ended,