I see there’s a Milebush recorded in the 1797 Horse Tax Rolls in Scotland: https://scotlandsplaces.gov.uk/digital-volumes/historical-tax-rolls/farm-horse-tax-rolls-1797-1798/farm-horse-tax-1797-1798-volume-02/76. I’ll keep an eye out for other ones. Closest equivalent in Dumfries and Galloway I can think of is Two Mile Trees: https://twitter.com/dgplacenames/status/1475949822255546377