Out of Pod Experience

50 GBP is not a lot of cash for a video card, and even a little bit of extra cash for the budget would increase the performance you get radically.
Trying SLI//Crossfire with weaker video cards can become a frustrating affair, you'd better just get a different much better single card later on instead.

Best card you can hope for that fits the 50 GBP budget would be a 1GB GDDR5 Radeon HD 6670.
http://www.scan.co.uk/products/1gb-asus-hd-6670-4000mhz-gddr5-gpu-810mhz-480-stream-processors-displayport-dvi-i-hdmi
It should be able to run two EVE clients at pretty high graphic detail level in FullHD resolution at close to 50 FPS while hangar ship-spinning.

P.S. That is, unless you insist on NVIDIA ?
In that case, best thing you can buy for 50 GBP or less would be a GT 630, which should only be able to get you ~35 FPS under similar circumstances.

6770 = 5770

I'm acutely aware of this, because I purchased a 5770 as 6770s were released, and enjoyed an atypical 2-generation life cycle out of the same card.

don't use HD6xxx series. go higher or lower. I would send you my used 5770 for free, but shipping across the atlantic is murder

don't buy used--the risk is too high they've been overclocked.
bad part of finding them new, is Apple has hoarded them for their current Mac Pro.

5770 runs three clients just fine

//**note: to utilize the third monitor on 5xxx and 6xxx gen eyefinity, you'll need a rather expensive -powered- active adapter with the USB for power... such as this Sapphire active displayport adapter. they're around $100 USD, and a difficult purchase when you wish the much cheaper unpowered adapters would work.

if you're only trying to push one monitor for the time being, you could go ATI 4xxx series or NVIDIA 4xx series-- anything with 1GB. those are $30 USD

but if you find a 5770, you can dual box stock, and you won't need to upgrade it later for just 2 clients

5770.. will allow you to avoid a necessary upgrade in the near future. as long as it's just 2 clients

available in the US for $125, which is just shy of your £100 mark

lemme see if... what the shipping is like from here to you.

last time i offered to ship something to europe, shipping was $200, so don't get your hopes up, but i'm serious about offering my card free.

this is the specific one i have

blah. yeah still basically the same cost as buying one new.

find a Radeon 4000 series with 1 gig, or a Nvidia 400 series with 1 gig, and that should be good for now... cheap, dependable for the time being. pretty sure both offer dual monitor support

yeah that's a little more than stopgap but it comes with assassin's creed III!

(I've been meaning to get my hands on an activation code for that game.)

A stock version should theoretically be able to easily run 3 simultaneous clients at around 60 FPS each, at the same settings listed before for the other cards (those that could only do 2 of them at 50 or even just 35), and that one might do a tiny bit better since it's a lightly factory-overclocked version.
It can also drive 3 monitors at the same time, just note that you might possibly need some cable adapters, depending on the card output types and your monitor cable types.
However, I am a bit concerned about it having just 1GB of RAM if you plan to go with high texture detail for 3 clients on two or more FullHD monitors - in that case, you might need to scale down texture detail and/or resolution a bit in order to not get the occasional "also using system RAM for buffering" stutters.

P.S.

In comparison, the Radeon HD 5770 // 6670 should be able to pull roughly 55 FPS out of 3 simultaneous clients under said circumstances, so very close to what a GTX 650 can do.
Power-wise, stock version HD 5770 needs 108 W, while a stock version GTX 650 only needs 64 W (but that exact one you linked probably draws closer to 75 W, possibly even more than 80 W, due to the factory overclock).

If you can find one for sale for noticeably less cash though, and you don't mind the extra power drain then sure, why not, just go for it.
Personally I'd go with a stock GTX 650 (but one that has active cooling, not just a heatsink) if the prices are fairly close.

im aware on possibly needing adapters i will only ever be running 2 monitors i think unless i can convince the misses that 3 will look nice on my desk in the living room :)

i only ever normally run 2 clients max as said if i do run 3 it will only be for mining so not too bothered if i have to trun detail down just dont want it too run slow because the gpu isnt powerful enuff.

plus, that 650 could be put into crossfire when you upgrade, or just leave it for extra physx processing power. the motherboard you are looking at does have 2 video card slots, but I'm not really up to date on ATI chipsets so I don't know what kind of throughput you could expect out of that.

Caleidascope, you have a theme song. did you know this?