So, we have loaded speed at sea level at 329mph, after bombs gone at sea level of 333mph. Best altitude is 28,500ft where it does 408mph with bombs and 419mph afters bombs are gone.
At 28k, The P-51D in AH does ~430mph, the 109K-4 ~440mph - and that's with WEP. That's very little speed advantage for those fighters, if they aren't at altitude before meeting the Mossie, they will have a very hard time to catch up before the bombs are falling, if at all.
I would try to take a P-47M (~460 mph) and get to alt once I just suspect there is a Mossie lifting somewhere, so I can get the necessary altitude before the enemy breaks dar.
For me as a buff hunter, the Mossie could be an interesting "problem", having to read the map and plan my flight just like the pilot of that unarmed bomber. I see fun ahead!