Typing Czech characters on a UK keyboard

So, here I am using both KDE and Gnome on Debian systems and intermittently trying to acquire a smattering of Czech.

Czech uses the Roman alphabet, but has some accented characters.

I want to be able to type these characters from my GB layout 105 key PC keyboard under KDE. How can I do it? Note that the keyboard has only GB markings. I don't type enough Czech to warrant using a .cz keyboard.

á, é, í, ó, ú, ý č, ď, ň, ř, š, ť, ž ů