I thought I would update.
I have been given sumatriptan again by my GP, which does seem to do the trick, but after having these in the past the effect wears off gradually.
I researched a lot about migraine relief and natural remedies, and found that peppermint and lavender oil is really good for helping. I purchased both from eBay £0.99 each (or you can buy from other online or retail shops) rather cheaply. If you dilute the oil with some water (if you don't dilute enough it can irritate) and rub a little on your temples and across your forehead, it seems to ease the migraine instantly. Reapply if necessary, but I recommend taking a pain relief with this too.
I also heard that having potato slices placed on the forehead helps too- I tried this once but probably not long enough. Will do this again and update.
Let me know if this helps others
I'm also aiming to get a Daith piercing shortly, and will update!