A Scottish MA(Hons) is a first degree, equivalent to an English BA(Hons). It is not a postgraduate Masters degree, which people typically need when they are intending to do a PhD. Scottish postgraduate taught Masters arts degrees are typically not MA degrees, but titled various things like MLitt or MPhil. It can be confusing! I have a Scottish MPhil which is a taught PG Masters, equivalent to an English MA.
You will almost certainly need to do a taught postgraduate Masters degree on the way to doing a PhD, unless you can get direct entry to a PhD without one. Which is unusual in the arts/humanities field.
(briefly delurking!)