Sacha wrote:

............ However, we
noticed that, in Jersey, mimosa is coming into flower, daffodils are a *lot*
further advanced than here, though not yet in bloom,

All of the big 'mimosas' (Acacia dealbata) here are just starting to
flower. Some daffs are open and looking very cheery in parts of
Torbay, along with early snowdrops and a few very precocious clumps of
Dutch Crocus. I don't 'do' spring bulbs in my garden, save a few pale
lemon, tulips out front. These never show much before the middle of
January, but this year they are already 6" high. There are some
painfully neglected Zantedsechias in the same spot (neglected because
they are allowed to dry out in summer and become fully dormant from
July until October rains) and these are showing the tips of their first
flowers in their leaf axils.

... and the buds on the Magnolias are fat and promising.

Yes, same here too. At first I thought it was just a few large
Magnolia stellata, but several soulangeana types are also as advanced.
The average minimum temperature here in December was a nearly
sub-tropical 10C and with the trend seeming to continue, we might get a
very early spring. However, I'm all too aware that there is a painful
tendency for February to provide a bitter week or so and that usually
brings things to a juddering halt.