The front sprocket nut and washer saga

[unfazed]

Never done it myself so I'm no expert but don't you need to replace the chain & sprockets as a set?

I agree,
I always replace 3 front sprockets to one chain and rear sprockets and chain and rear sprocket last in excess of 40000miles.
Replacing the ful set everytime the front is a bit worn is totally unnecesssary. The front sprocket wears 3 times faster than the rear (15 teeth to 45 teeth). A well looked after chain will need the front replacing around the 10000 mile mark. That is about £21 for 3 sprockets compared to £150 to £200 for a full set.
I am on my third front sprocket with 39000 miles on the chain and rear sprocket with little or no chain lift off the rear sprocket.