In reply to Cneifion Arête:
There was a discussion about this a few years ago.
https://www.ukhillwalking.com/forums/hill_talk/main_gully_glyder_fach-62251...
The consensus seems to be that it's mostly Grade 1, but with a meaty move which might be tricky if you're not a climber. Ashton doesn't seem to rate this much, but a lot of people seem to have struggled there, so take care.
The thing about grades, particularly for scrambles, is that they are only a guideline. How difficult you find them can depend on many factors, including weather conditions but also your own height and build. Never assume that you will always be able to get up something at a particular grade, and always be prepared to turn back if you find it harder than you expected (if it's a lot harder you're probably off-route). Scrambling is more dangerous than rock climbing because you probably don't have the same gear to protect you.