I was on my way to say something about placement for monitor speakers and 8″s being a bit big for my taste for the small space of home/project studios, when I re-read your post and saw you plan on using them in a different setting.
And THAT changes my reply drastically.
My advice would be to NOT buy (DJ) monitors. Monitor speakers are made to sound neutral not nice. Listening to them becomes tiring after a while. It’s inherent to the design. The KRKs have a little coloring which somehow seems to make that effect slightly less without interfering too much with creating too much color.
Over the years I have found that high quality (hifi or better) and DJ-ing somehow don’t go together well. DJ-ing is typically the realm of PA systems. Where volume and a certain amount of color are not only expected but necessary to do the job.
You could of course opt for some good quality small PA speakers (here 8 or 10″ would be a good size) that will give you decent sound quality with the option of going high volume should you want to.
There is a good alternative, but you might need to save up a little longer (although I have seen them online for 590 euro which isn’t too far off 400 GBP). Take a look at the HK audio Lucas Nano 300 (or 600). It’s a sub with two really small satellites that packs a punch that belies it’s size while still bringing decent sound quality. As a bonus it’s highly transportable so any house/b’day/bbq/garden party at friends and you are good to go.