I know hwo to do it using VBA but was asked to perform using only
formulaes, so if anyone could help me?

A field in the spreadsheet contains a string built up by up to 8
numbers separated by various numbers of spaces,

eg: "12 45 3 2 12 23 2 "

Now the output needs to be also a string with the numbers, but only
separated by a single space, that is:

"12 45 3 2 12 23 2"

Can you help me with a formula for that ? :)

Thanks in advance!