Any question answered...

What cranks and BB should I get for my fixed commuter ?

I have a 68mm BB shell, a 130 BCD chainring, a hub with a 53.5mm chainline, a preference for 175mm cranks and budget of about £100.

sram apex maybe

53.5 is a pretty wide chainline. A road chainset with an external BB won't be adjustable, short of spacing the chainring out from the spider. Using the inner ring as a spacer will be about right, and saves the need to buy new chainring bolts.
FC-4600 is £71 or thereabouts, plus £14 for the BB

£58 and £12 if you can wait a couple of weeks for the cranks

I have a dura-ace 7800 group set on my bike. It's pug ugly and I dont like the shifters. I want to trade it for a similar age/spec Campagnolo group. Which group would this be? I have no idea about Campagnolo parts.

Whatever the last 10spd Record groupset was?

SRAM Red might work out a bit cheaper, and you'll be able to keep your rear wheel.

Would I be silly to de-decal a pair of 1995 Campag Ventos?

The two wheels have different style stickers and the both look shit anyway.

"I have a dura-ace 7800 group set on my bike. It's pug ugly and I dont like the shifters. I want to trade it for a similar age/spec Campagnolo group. Which group would this be? I have no idea about Campagnolo parts."

If you have no idea about Campagnolo parts, how exactly do you know that you want a Campagnolo Gruppo?

*Don't get me wrong, I love classic Campagnolo, just asking...

Would I be silly to de-decal a pair of 1995 Campag Ventos?

The two wheels have different style stickers and the both look shit anyway.

If that's what you want, do it.

...but lord have mercy on your soul when the retro campagnolo gods strike.

That's what I thought. I'll leave the Campag labels, it's just the Vento bit I don't like.

Retrobike can't touch me here, right?

They are your wheels, do what you like to them.

The hub on my Haro Mary SS seems shot. 50% of the time pedalling works and the pawls engage. The rest the freehub just spins freely in both directions.

I know absolutely nothing about single speed hubs using short freehub style bodies. Is there a cheap solution out there? A Novatech or similar go to hub that's a default choice for replacement? Could get a regular fixed disc hub and run a freewheel without chainline issues? Any benefits to a particular solution (other than that I already have 2 or three cassette style cogs)? Should I just post a wanted ad on singletrack world for a whole wheel? Should I see it as a sign to stick a mech hanger on it and shift to 1x9?

some spanish polo players were staying with me a while back and this very thing happened, they just dismantled the block carrier / cog carrier and had a look at the pawls inside. it seemed they just needed lubrication / cleaning as they weren't sprininging back , once done they were back to fine. once re mantled they engaged perfectly and they almost won the tourney

I have a dura-ace 7800 group set on my bike. It's pug ugly and I dont like the shifters. I want to trade it for a similar age/spec Campagnolo group. Which group would this be? I have no idea about Campagnolo parts.

Shimano is much nicer than Campy

Everton are much better than Liverpool.

Spurs are apparently better than Arsenal.

But it is spring.

Bumming is real.

some spanish polo players were staying with me a while back and this very thing happened, they just dismantled the block carrier / cog carrier and had a look at the pawls inside. it seemed they just needed lubrication / cleaning as they weren't sprininging back , once done they were back to fine. once re mantled they engaged perfectly and they almost won the tourney

This, I think, is going to be the way I go. Seems like anything else is going to be a ball ache and expensive.

How do all these SS MTBs you see run? Surly style threaded disc hubs with freewheels? If that's so, I'm surprised there aren't any readily available, super cheap versions out there.

I posted earlier. There are. I found some. It's stoopid of me to say it and not post the links, but I can't find them now. But honest, there were some. I'm going to search my browser history.

OK, this is what I found: http://www.chainreactioncycles.com/Models.aspx?ModelID=69093&gclid=CM_R3YCB7bQCFW7HtAodYxsAKw&PartnerID=2812&utm_source=Awin&utm_medium=link&utmcampaign=generic&$ja=tsid:41244|cgn:awin|kw:101164&awc=2698_1361976008_94f985d8bd8725e32c9d1fa927a409c7 £50, which is not so bad.

And this was suggested to me: http://www.tartybikes.co.uk/135mm_free_hubs/hope_pro_2_evo_trials_ss/c148p11557.html £150, which is quite expensive.

And really, there were others, I can't find them.

I got a Monty 135mm hub off ebay which has a 6-bolt mount and a normal thread for a freewheel (rather than a cassette body). No idea where the original owner got it or how much it was meant to cost.

Why does no one listen to me?

Because without an avatar you're clearly a noob who knows nothing. ;)

Are Miche carriers that cheese like to not be worth the hassle?

iirc Halo were making a hub with a splined sprocket using the Shimano spline. I can't remember if it was only fixed though.

Steady, I'm kidding. I am not thinking the Avatar would be the tell, would it not be the member number?

I was looking up those DMR hubs the other day. A few people were moaning that the freebub was a bit shite.I then looked at the cost of a replacement freehub - £12. Even if it dies every other year they have a reputation of being pretty bombproof.

There you go. It's a decent recommendation.