Back on 22nd April, I observed that the Brown Hairstreak eggs within Brighton, had now started to hatch.
Following this, I was amazed to actually locate one of the caterpillars nearby, a first for me. The length of the caterpillar was hovering around 1mm. I described to my friend Dave (David) Cook: "The Caterpillar was sitting on a yet expanded leaf, so the form of the leaf was tubular, with the caterpillar resting on the underside - as expected."
Returning to the same site yesterday (28th April),I was pleased to locate a second Brown Hairstreak caterpillar, pictured below - there are four hatched eggs on this same plant, plus another un-hatched egg, in this case, Wild Damson has been used. The two caterpillars now measuring 2mm in length. There is evident feeding damage to the leaves in my photo. Given their size, they were fairly active, moving about 2" in the short time I was there, occasionally taking up rather exposed locations.
For those that are worried

that I have turned my back on the White-letter Hairstreak life-cycle, don't worry, though due to unfortunate circumstances my study site of two years is no longer suitable for undertaking detailed observations. I have located two White-letter Hairstreak caterpillars so far this year, at two different sites, one of which rightfully being Hollingbury Park.
White-letter Hairstreak, hatched egg, Hollingbury Park, 14th April.
White-letter Hairstreak, caterpillar, 9mm in length, Brighton, 28th April.
Purple Hairstreak, hatched egg, Brighton, 19th April.
Purple Hairstreak caterpillar photo, hopefully to follow soon!
UPDATE: Purple Hairstreak, 3.5mm caterpillar, Brighton, 1st May.
Back on 22nd April I saw my first Green Hairstreak of the year, though this was my only view

:
I really want to photograph a Green Hairstreak egg this year, I just need to observe an egg-laying female at a local site, wish me luck!
Brown Hairstreak, hatched egg on Wild Damson, Hollingbury Hill Fort, Brighton, 1st May.
Interesting fact, this egg and another I found higher on another branch, were laid just above an elevation of 584 feet (178 m) above sea level.