Thanks Pauline, we spend hours looking for/at them

but yes it certainly is very fascinating and rewarding pastime
Thanks David, I certainly will give updates on their progress.
Thanks Paul, the largest two Purple Hairstreak larvae are in a draughty utility room with single glazed windows and a plastic roof. Its very cool at night but is warmer in the daytime but the larvae are not subjected to wind or rain.
Thanks Wurzel, they are almost always well hidden but hopefully as they grow they will find it harder to hide
Our first two Purple Hairstreak larvae continue to grow at a great rate and yesterday (3rd April) moulted again. They are now 19 days old and still spend their time resting on the Oak buds or climbing amoung the Oak leaves. They show no signs at present of spinning a silk web around the expanding buds to form a cocoon to hide in.
More of the Purple Hairstreak eggs that we took out of the fridge on Monday 31st March have hatched. Although most have bored into the buds, several of the hatched larvae surprisingly stayed on the outside, seemingly making no attempt to bore inside. One in particular remained on the outside for 24 hours so must therefore have been feeding on the outer surface of the bud.
We were caught out today when one of our Orange-tips emerged, unfortunately we missed the emergence but found a beautiful female waiting for us when we got home. Eight months since pupation, she is a sight for sore eyes

She is now out in the garden roosting on an Erysimum Bowles Mauve flower and was still there when I looked just before dark. We now also have a male about to emerge, hope he waits until the morning!