Spyke,
I have seen some awful things done to motors. I did them myself mostly back when I thought the world revolved around going 1/4 mile as fast as possible.
But in this case, the BSA budget being tight for you as it is for me, before I had this bored to +80, I would look into a re-sleeve really well- not for right now, but for later. Make sure that by going out to +80 you are not taking so much from the bores that a re-sleeve is no longer possible. These barrels are hard to come by, and saving some now but costing a fortune later is not saving at all.
Richard has had no problems at +80, so I would say give it a try as long as a good sleeve is still do-able next major rebuild.
Lee