Power wise, you should have no problem. The Xarus 5000 are very efficient.
Good luck finding a pair though. Have you contacted Hughes? Do they have any idea when, and if, they will get more in?
As an alternative, you might consider these. I've never heard them, but some of their other speakers are well liked for the very low price they charge.
Eltax - HiFi Since 1959 Products
Eltax CONCEPT 400 Beech | Per Pair | Richer Sounds
Eltax CONCEPT 400 Black | Per Pair | Richer Sounds
The only thing I can say about the company Eltax is that they have been in business for 50 years, if they were screwing up their speaker designs, they would have been out of business a long time ago.
On the other hand, you can only expect just so much from a £150/pr speaker.
Worth a look, and you might even be able to get a demo at Richer Sounds.
Here is another possibility, Infinity Beta 40 at £200/pr-
http://www.hiwayhifi.com/site/product.asp?section=1&cat=42&sub=244&prod=29877
Again, all I know about Infinity is that they are well regarded, and get written up in a lot of HiFi magazines. I think the Beta series is discontinued. But for someone on a budget, they might be worth a look.
A quick search of the Google-UK for reviews indicates that most people are extremely pleased with the Infinity's, rating them consistently 4 and 5 out of 5 stars. The speaker seem to have been released in 2004 at a suggested retail price of £499/pr.
Steve/bluewizard