Typing Czech characters on a UK keyboard under KDE

So, here I am using KDE 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.

Character How to type
á, é, í, ó, ú, ý Hold down AltGr, type ';', release both, type letter.
č, ď, ň, ř, š, ť, ž Hold down AltGr, then hold down Shift, type '@', release all, type letter.
ů Hold down AltGr, then hold down Shift, type '{', release all, type letter.