The Vickers Wellesley was not an obvious and/or well known bomber of the Second World War - which should be pressed home by the "you'd think I'd remember something like this" effect of its appearance. Single engine mid-size bombers were already passing out of favor at the end of the inter-war period for the simple fact that they're very, very slow. Therefore, even a "modern" monoplane one with light weight is not really a good idea - the fact its predecessor/prototype for government contract was a biplane *and won* (1930) is probably a statement on just how hard everyone else was pushing the envelope - which is to say, less than you'd expect.
The Wellesley is most significant for being the first production plane built by Vickers with the "basket-weave" geodetic aluminum rib construction that was later put to use in the famous Wellington. Below, a picture of the wing structure after damage...
...and the tail section of a Wellington:
This setup has extraordinary strength, light weight, and is very difficult to destroy - the plane, that is - it couldn't stop a bullet from hitting the crew worth anything. It was originally developed by the genius Sir Barnes Wallis (known for the dambuster bomb, the "Grand Slam", and many other things) for use in airships. One thing it makes harder, though, is the proper locating of access to the outside. The strength of the fuselage depends on being a complete tube as much as possible, so making bomb bays is hard work. Or, it would be, if they'd really tried on the Wellesley. They didn't. In the picture below, you will see two streamlined pods under the wings - these are external bomb bays. Yeah...
You will notice that in the desert combat picture of the Wellesley, it does not have full canopies. Nor does this one (actually flying with a forward canopy, but open):
One assumes that much like some of the planes used in the south Pacific, it was much too hot to try to fly low altitude missions in the sun anyway - and it's not like the Wellesley was fast enough for that to make a big difference (cruise, 180mph). Having a rear gun position - also helpful, and worth a little bit of breeze.
By the outbreak of WWII, almost all the Wellesleys were out of service or shunted off out of sight, so their combat action took place in North Africa against the Italians - a forgotten campaign if ever there was one. One was lost to the man who was to become the top biplane ace of WWII (yes, really a thing that happened), flying a Fiat C.R. 42 Falco:
There is one aspect in which the Wellesley excelled, however: range. A flight of modified Wellesleys flew non-stop from Egypt to Australia in 1938, a distance record that would not be broken until after the war, and which is still unbroken for a single-engine aircraft *today*.
Pictures - respective Wikipedia articles other than cutaway (airwar.ru, probably scanned from Avions) and Wellington tail section (albumwar2, presumed public domain).