Its personal choice but with mine i wanted to wait till after my second scan to make sure everything was good.But not to far along going out shopping sounded like hell lol.Do what feels right for you not other people
kids under 2 need one more layer than your wearing to keep warm
so for example
cold day
mittens
hat
vest
sleepsuit
coat with thick blanket or snowsuit
so a few changes a day ,then work out how often you want to wash things.Should give you a idea of how many .I recommend asda for baby clothes
Now for car seat go to a facebook group Car Seat Advice UK ,This will help you not only find the safest car seat but one that fits your car.
pram what ever fits best in the boot of your car or what ever is lightweight for public transit
cot for upstairs and Moses basket for downstairs if you want one,flat sheets,cellular blankets .When they start kicking the covers off a baby sleeping bag
vibrate chair optional i find it helps them sleep when they are suffering with gas .Swings are good but they tend to threw up in them
breast or bottle up to you ,but for bottle you need steam steriliser bottles the right teats,bottle brush,unscented washing up liquid .Breast just some button up shirts make sure you pack a spare in the changing bag in case they threw up on you .Breast pads i recommend asda ones they are most comfortable .A breastfeeding cover if your feeling shy
i am sure theres a bunch i missed but hopefully someone will cover that lol