Okay, did some research.  But first, have you PMed KevH?  He's in the UK and will have a better idea of who sells what, where.

First of all, anybody who claims Behringer's stuff sounds really good, well, let's just say I don't trust their hearing.  For example, you indicated that some folks on vdrums commented favorably on the Behringer K900FX and yet, you listen to it and it sounds like crap.  Go with what *your* ears tell you.  I've never met any musician, amateur or pro, who's opinion I respect have anything but poor words to say about Behringer gear.  They are noisy with substandard sound quality, hell, you're hearing that yourself.  And we haven't even mentioned reliability.

Yeah, I have a 24 channel Berhinger sound board.  It's been fixed twice and fortunately the last fix took and in the 4 years since, we've not had any problems.  But it never goes far from our house either and we treat it with care.  It doesn't seem to contribute much to noise or poor signal quality but then again, we're talking powered speaker cabinets here.

I'm not sure what's available in the UK.  I mean sure, all the standbye stuff like Mackie and JBL are there but I'm assuming you can't/don't want to spend 480 pounds for a Mackie SRM450 V2 (as an example).

Have you looked at Kustom?
http://www.kustom.com/product_family.aspx?TypeID=8&FamilyID=83&Tab=0

I found a place in the UK that carried them:
http://www.jhs.co.uk/kustompa.html

Their powered cabinet, the KSC15P, runs 259 pounds.  It's a modest 100 watts but if you were looking at the DA200S, this will be similar in terms of power.  There's been one thread on vdrums about it so we don't have a lot of data points but at least one person who's opinion I respect on there has had good experience with this budget system.

Be forewarned that Kustom's equipment has a good rep for sounding good but a mixed rep for reliability.

Here's a possibility:
http://www.whybuynew.co.uk/dj-equipment/dj-speakers/mackie-thump-th15a-active-speakers-pair.htm

Look over on the right side at the "B Stock" listing.  You can get one of these for less than 200 quid.  Not bad really.  Of course the reviews on vdrums have been mixed but there haven't been that many reviews now that I look at em.  I guess if push came to shove, I'd listen to the TH15A and the Kustom powered cabinet and see which one sounds better and go for that as a lower priced amp for my kit.

Another well-rated product, the RCF ART line can be found here:
http://www.pricerunner.co.uk/pl/92-387829/Speakers/RCF-ART-312A-Compare-Prices

I guess the conclusion I draw from this is any of the higher-rated amps good for edrumming will run you between 4-500 quid (see below about the Roland KC-550) if purchased new.

Have you thought about used?  Is Peavey equipment available in the UK?  The new PR15 is nice but it's also in the 400+ pound range price wise.  However, there's always tons of used Peavey cabinets for sale just about everywhere.  It's worth keeping an eye out for.

Same for the Roland KC series of keyboard monitors.  Per the vdrums sticky, the KC-550 would be ideal or if you could find a TDA-700 used, you'd be set.  I see that a new KC-550 amp costs about the same as a Mackie SRM450 v2.  I'd probably get the Roland if those were my only two choices if going new.  

As is typical with going used, you have to be diligent about looking and patient and then pounce when you finally see what you want.