Because of the state of the relationship between the two companies the MS&LR was unhappy being wholly reliant on the Met for access to London and, unlike its railway to the north, south of Aylesbury there were several speed restrictions and long climbs, up to 1 in 90 in places.
Forholdet mellem de to selskaber gjorde, at MS&LR var utilfreds med at være fuldstændigt afhængig af Met for at få adgang til London, og modsat deres jernbane mod nord var der syd for Aylesbury adskillige hastighedsbegrænsninger og lange stigninger på op til 1:90.