Good day

[Gary Stephenson]

Welcome Philip

[chubbbramah]

Welcome!
If you need key blanks
https://www.morlandslocks.co.uk/gb/
can probably help you.
However, lever keys use wire gauge sizes, and you will need the correct size blank for Chubb cabinet locks, including locks using pipe keys. Keys, and locks, are made in many sizes; locksmiths use a gauge like this for measuring keys — there are other gauges for measuring pin tumbler keys and pins:
https://www.lockstation.co.uk/mortic...guage-keygauge
It is not that easy to find online instructions for fitting lever lock keys by hand. Most instructions are for US locks (they also call a locking lever handle a 'lever lock' :-( ).
A vice, some flat needle files, and a candle wil be useful; also some spare blanks. There is a good chance you will not make it right first time, just start again.
Some, mostly older, diy books describe the procedure. Or have a word with a friendly local locksmith if you have one within reach.