It is interesting if comparing the sheep counting systems around the UK with a comparison between the celtic languages of NW Europe way of counting. It all starts to get very confusing. The sheep counting system seems to borrow from both Brythonic and Goidelic languages.
I do not know if minding your P's and Q's has it's origin here but it neatly summarises the difference.
" one major difference between the two branches of modern Celtic languages, Goidelic and Brythonic. Goidelic languages (Irish, Scottish-Gaelic, and Manx) can also be classified as Q-Celtic, while the Brythonic languages (Breton, Welsh, and Cornish) can be labeled P-Celtic. This difference refers to a sound change whereby the Q-Celtic languages, in branching off from the other Celtic languages, replaced bilabial stops (represented by “P”) with velar stops (represented by “Q”). Hence, questions words in modern Breton such as pe, pet, penaos, peur are cognates with the Irish cé, cad, conas, and cá huair (who, what, how, when)"

https://www.omniglot.com/language/numbers/celtic.htm

https://en.wikipedia.org/wiki/Yan_Tan_Tethera

I find it very interesting but also very confusing. I need to put them all in one spreadsheet or use a second screen in order to closely compare them.
There is a school of thought that a single sound shift should not divide a language.