Confidence: It's likely to be this, but I can't be certain.
Notes: This does have an orange look about it, but I think it may just be a bit worn. It is grey-ish in colour with a faint orange/yellow border. The forewing is strongly curved towards the tip in this species as well. Also, given the date of this observation it is more likely to be dingy because the oranges are out earlier in the year.