Replace multiple numerical values with text

I am currently working on a sales table in PowerQuery which contains a list of 'Customer Numbers' as numerical values. Most of these are reoccuring customers with a single 'Customer Number' but there is an growing list of 'Customer Numbers' which are generated for one time sales.

These have an 8 digit format as opposed to the stadard vaiation of no more than  4 digits.

I want to replace all values in this table over say 7 digits or greater than 10000000 with a text frase of "Internal". 

Can someone please help with a solution in PowerQuery.