Chaffinch (Apr, Herts).
The Greenfinch has two song types, a wheeze and a trill (Apr, Herts).
Greenfinch including mimicry in its song; there are over a dozen different calls, including chaffinch, dunnock, blackbird and pied wagtail (May, Essex).
Goldfinch (Apr, Norfolk).
Linnet singing at dawn high in a tree (Apr, Suffolk).
Siskin. Note the diagnostic wheeze at the end (Apr, Herts)