I know where you are coming from, I am very, very allergic to oil on the wrong side of the aluminum or steel...people tend to say, if it doesn't drip, it is sweating and not a problem, allthough this is certainly true as no engine ever lost enough oil by sweating to starve...but I always want it gone as it will always become worse and become a real leak...so why not fix it right away, nothing so embarassing as driving away with your supercar and people find a puddle of oil left on the street.
Off course in your case it might well be possible that in this time you have 2 sweating area's, the main seal at the back and the problem at the front. If the sweating isn't too bad, I think I would leave the back for what it is untill you need to be there anyway, it is a sh*t job. Timing chain though is pretty straight forward, and you'll be able to put the Roe cracnk bolt assembly in there, to avoid it coming loose, that off course only when this turns out to be the problem. Make sure you have a big, big torque wrench for the crank bolt, it is lots of nm on it.