If the availability in the UK for a new KS 120 is similar to the availability in Germany, you will have a long wait...at any price. My dealer in Mannheim had one, but I waited about an hour too long to commit to the purchase and it was gone. I can put my name on the long wait list for a new KS 120, but the dealer can't give me an idea on when they will be available again.
A few places do look to be out of stock. I read on the Festool Owners Group that Festool are having problems obtaining a part for the Kapex through their normal supply chain so are trying to source elsewhere.
In America there was a special promotion in February on the Kapex, the saws were meant to ship 1st April, they haven't shipped yet because they don't have any!