It turns out the Hippolais/Iduna Warbler seen yesterday was in fact a
BOOTED WARBLER. My initial impression, and continued impression that the bird was a Sykes's Warbler was wrong unfortunately. Although I was leaning more towards Sykes's due to my personnel thoughts on the bill, facial pattern, overall colouration and tail length being suggestive of this species, my concerns after flicking through certain literature regarding the tertial patterning and primary projection proved to be too much in favour of Booted. However other photos have shown the features suggestive of Booted which I didn't manage to capture. An average percentage of the exposed primary projection comes in at roughly 51%, which is slightly longer than what would be expected in a Sykes's.
None the less, a cracking bird for the county only being the 5th record for Sussex, and very pleased to have been part of this very educational bird, even if I failed to id. the bird correctly. Maybe when I eventually see a Sykes's it will all be so straight forward........no chance!!
Booted Warbler at Climping