Help extracting single numbers

Hi I am trying to isolate single numbers (the numbers are size 6, 7, 8 and 9) and nothing else. The numbers I want have a space after if they have anything else I needs to be ignored
I am using power query to try and achieve this
Attachment 736502
As you can see from the picture I have managed to get rid of the 1st 4 numbers (column B) but I need to isolate the single numbers (with a space afterwards)
I want from 6 STND ... 6 as an example but from lets say 2XL AG ... I want it blank or null

Hope this makes sense

Thanks
Kim