Showers Pass Refuge Jacket, end of searching.
Shell type, preferably Goretex or equivalent : yep,
Medium weight, not after a super lightweight jacket, this is more for wearing all day rather than stuffing n a camelback in case it rains : yep,
Zipped front pocket for phone : yep, also fully waterproof
Good fit and durability : yep, I’ve worn mine for trail building when hoofing rocks about, days out on the farm covered in shite and wrestling wi bullocks, covered in mud from the farm quads and i even wear it mtb’ing with no ill effects to it’s waterproofness – it has survived a helluva abuse so far.
Highish collar, I like to zip out droughts : yep, high lined collar with a brilliant detachable hood that fits over a helmet.
Ideally red as that is fastest : yep, comes in super fast red or stealth black.
And it come with massive chest vents so overheating is never a worry, ….it also comes with a popper drop down rear so your arse is protected when wet/muddy.
around £150 budget : Oh….that may be an issue but believe me – i used to always be searching for that one perfect jacket and the Showers Pass Refuge is perfect, check out any review you will find online – they all sing it’s praises.