Yea it probably doesnt have a compression
issue if it starts easy but sometimes, on a multi cylinder, its hard to tell. Its more likely oil control ring or v/v seals
but good to check. Anyway when you pull the injectors for test you'll see if ones oily.
You should be able to get 20w- 50 or 60 ok even if you cant find the 25w-70.
We can get it from supercheap auto in NZ so I'm sure you can get it in Brizzy.
Changing frm 15w-40 to 20w-50 upped the oil pressure by 5lb hot in our Yammer just as an aside. Not sure how much difference in consumption it will make but worth a try I reckon. The 20w-50 Gulf western is often real cheap
too if money
is a factor.