Keep it in perspective. It was not a dedicated Fighter-bomber.
The first Spit-bombers were field modified Spitfire Vs from Malta when they went on the offensive.
There were trials with any number of variants in regards to dropping bombs. In early 44 the first couple of England based Spitfire IX squadrons got Spits modified to carry bombs. These were Spit IX with universal wings and bomb racks added. The stress on the wings was a problem if the bomb failed to release as was the case on a few occasions. They were used to go after V-1 sites and the like. Post D-Day the Spitfire LFIXe and XVIe with clipped and strengthened wings arrived with a centerline bomb rack and wing racks or rocket rails. These were used by 2 TAF in the fighter bomber role. They did the job they were given.
Probably the most well known Spitfire bombing run was the one made by six Spitfire XVI of 602 Squadron on March 18, 1945 when they ran a precision low level attack on the V1/V2 headquarters in The Hague on March 18th 1945.
A Spitfire XII pilot who I got to know fairly well finished the war on XVIs flying ground attack. His take on it was that due to the Luftwaffe having dried up, they had nothing else to do with all the Allied fighters so they kept them busy dropping bombs. He was shot down dropping a 500 pounder on a Sub pen. He was still bitter about it as they all knew that there was no way the bombs were going to do any damage. He finished the war as a POW.
I've never talked to or corresponded with a Spit pilot who thought a Spitfire carrying bombs was a good idea. But they were also fighter pilots not bomber pilots and it was never going to feel right.
As a side note, the Griffon Spitfires were considered better for dropping bombs as the view over the nose was better then the Merlin birds.
Spitfire XII MB878 that was used in "Trial Mareth" to test the XII's compatibility with dive bombing.

The Spit XII squadrons never dropped a bomb operationally, but did get time lugging them in practice for the possibility. They did lose one XII during the dive bombing practice too possibly to the problem with the bomb not coming unstuck.
The bomb release mechanism was basically a cable running into the cockpit that the pilot pulled. It was the same as used for the DT. Another Spit XII pilot I talked to had it come off in his hand when he tried to drop his DT. No luck and he was unable to switch tanks so he ended up crash landing and becoming a POW.