Some more great advice, thanks. yeah, well I work on a building site, hence me not bothering to replace anything, but now I'm parking the bike outside, and am sick of jumping gears, so I'm upgrading now the bike is out of the dust. So here's what I've done:

-Brand new jockey wheels and chain.
-Middle chain ring: I didn't realise this until I looked at brand new chainrings, but the middle one is not as square or rounded as thre large and small ones. The spikes are quite sharp, so I think my one has a little life still left in it. I was expecting it started life much squarer (if that makes sense). So I'll keep those for now

Having fitted the new chain, gears 1-4 on the cassette are fine, but 5-7 are jumping, probably because they are worn and I use them more than the others.

I could just replace the cassette, but I have 4 cassettes sitting in my shed. Most of which didn't get much life out of them (I have terrible post war mentality - waste not want not!!). Two of them, 8 speeds, the 8th gear cracked. But the rest of the cogs seemed ok

So I removed my 7 speed last night, and put on an 8 speed (with the 8th smallest cog missing).

I had to remove one spacer I had on the freehub, so the position may have shifted.

What's strange is that in 1st and 3rd chainring, all gears work fine, but in 2nd chainring, most the gears keep jumping


Terribly confusing I know!

here is the state of my 8 speed (now 7 speed) cassette:

20140813 083537
20140813 083549


If this is too much hassle, I'll just buy a new cassette

Thanks