Best cheap(ish) amp&dac to get?

Recently bought a pair of custom one pro's as an upgrade to my crossfade lp2's, wondering what amd&dac to get to go with them, my budget is up to £100 ($156), preferably available in england, I already imported these beyers and the import tax and other charges are absurd, so no shiit or mayflowers, unless they add tax on to the order. Also I was unsure whether a tube amplifier would be better or not, I do slightly prefer the "funner" tone of the lp2's. I listen to techno, trance, other electronic genre's, melodic death metal, rock and some piano music. Thanks for any advice :)

In that price range, the Fiio e17 comes to mind.  Should be widely available in Europe and the UK.  It can double as a standard usb amp/dac, and a portable amp as well.  Sound quality is good for the price, and it is fairly neutral (wont color your audio much).  If you want a warmer/"funner" sound many tube amps bring, you should be able to achieve that through an EQ for free.  

It wont quite be the same as a tube amp most likely, but it's a far more flexible choice.  For example, that tube amp sound may be great if you're listening to Jazz, but not so great if you're listening to metal etc.  By having a more neutral amp/dac, if gives you the flexibility to more easily adjust the sound to what music you happen to be listening to at the time.

I'm actually looking for something that's more a desktop amp & dac. I already have a portable amp from fiio. Someone else recommended an e10k, but it seems to be a bit bassy, any other recomendations?

Well, outside of Fiio and Audinst (which I've heard conflicting reports of bad quality control), I'm not really familiar with anything that's sold in Europe/UK, at least not in that price range.  I do know that the e10K is good for the price, but is a step or two down in most regards when compared to the e17 (which is why it's half the cost).  The e17 will work just fine as a desktop amp dac, but if you specifically want something that LOOKS like a desktop amp dac, then I suppose it's not the best choice.

The entry level stuff I'm familiar with is all US or Canadian made such as Schiit, JDS, (and thanks to Tek Syndicate) Mayflower etc.  Schiit has a UK distributor, and JDS ships internationally, but they're both out of your price range.  The only place I was able to find that sells a O2 based amp dac in the UK is Epiphany, but again, the price is above your budget (about £180).

In that price range, I keep coming back the the e17.  It's about the best amp dac you can find for the money.  It's not a real fleshed out price range for dedicated desktop amp dacs as far as I can tell.  But it does seem to be a sweetspot for portable amp dacs.  The Audioengine D1 also comes to mind, but it's a bit outside of your price range as well, and I'm unsure of UK availablity...  but maybe something to look into?

I actually have an E17, and it is more than enough to handle the Custom One. There are better options available though. I am just unsure of the pricing for you there, and also if you are ok with DIY (soldering). You could get an amp and then get a dac to go with it later on if that seems reasonable (which I think it is as the amp is much more important than the dac). You could look into the Little Dot I+, which is the right price, but I don't really know much about it. Not sure I can help you that much since you are on a tight budget and I am unfamiliar with the pricing there.

All that said, a Fiio E10k or an E07k should be fine. You can find plenty of reviews of those online if you are interested.

Awesome, thanks for the advice guys!
I have another question though, would a schiit magni & modi offer me much difference over the fiio e10k with the custom one pro's (/v moda crossfade lp's/sennhesier hd 439's, which are my other headphones)?
it'd be like 50% more than the e10k, since one of my friends offered to mail it to me as a "present" so I don't have to pay the outrageous tax and import fees.

You can use a Scarlett 2i2 as an amp, you can find them used at guitar center for $100 or less. And of course you can plug and xlr mic in to it. 

The Magni is a great little amp. Best for the price aside from diy as far as I can remember right now. It is just as good as an O2 from the comparisons that I have read. The modi, as a dac, is less important than the magni, but it is also great for the price. Schiit makes great products. If you can afford it, I would say go with Schiit. They are solid.

+1 to this. Amazing audio interface. Another one that is just as good as the 2i2 by Focusrite is the Audiobox 22VSL by Presonus or Audiobox USB (older version) or the Firestudio Mobile(firewire interface) (all by Presonus)