Firstly CONGRATULATIONS!
We did a John Lewis appointment prior to the arrival of our baby and they were very good and did not put us under any pressure to buy things we did not need, (there is so much on the market to dazzle you!) I really suffered with back pain after mine, so things like prams and baby baths were invaluable for me, but might well be a waste of money to you. Here goes:
These are the things I did use:
Baby bath (saved back and baby was very small so made the whole thing far easier)
Travel system, was brilliant and is still in use. The pram part was great and helped me get out every day and get my bottle back a bit too. However, although our baby was born small, they outgrow parts far quicker than you will be led to expect.
changing table-saved my back
Playmats various - have been used lots and now have been passed to a friend
Bouncer- was used for first month or two only until baby figured out how to escape, however was fab to have during that time.
Sensory, small toys, soft playbook, bath toys, books various and absolutely anything that lights up.
Lego night lights (£10 in argos I think and key part of our night time routine!)
Other posters are quite correct you will be inundated with loads of cutesy clothes, I did use mine, but doubt you will need to get many early on.
I failed to find shoes to fit until baby reached 3 months, but doubt there is ever a need for these.
Photo frames and keepsake box (got given loads of trinket bits that have no actual use but will be nice to look at later I suppose, but was good to have somewhere to stash them and get them all out of the way, Vera Wang musical silver hearts look shiny and cute but you will simply have no time for these fripperies, much less want to dust them all!)
Hooded towels worked great for us...
Highchair- works well and is not a flashy or overly big one, would advise waiting to see how big baby is as we find a huge variance and our little one only fitted in two we found on the market without slipping right through!
Things I did not need:
Baby advice/Gina Ford type of advice books. Just enjoy your baby, who will amaze you with their own abilities in dictating routines needs etc...
Bath/room thermometers. Common sense does not leave you when you have a baby!
Nappy bin- a normal pedal bin works just fine
Talcum powder-still sealed.
Nursing covers, just used baggy clothing and scarves.
Baby blenders/ gimmicky weaning plastic bits: I found a stick blender and lots of sealable plastic stacking pots in various sizes work well. Don't waste money on the tiny ones, you will spend your life filling, emptying and washing them.
Moses basket- useless, ridiculous and bloody cumbersome waste of money. It is now home to the never-ending pile of soft toys you naturally accumulate without ever having bought any..... biggest ever waste of money, was supposed to last 3 months and lasted about a fortnight (I told MIL too, but that's a whole other thread)
Bottle warmers/sterilising units/microwave.... 10 months on and still have not thought "maybe we should get one". Did get a sterilising tank for about £15 in Sainsbury's which I now use for all feeding tools, bowls etc... However if you formula feed I guess they might be a requirement
Top and tail bowl-cannot imagine why you would ever need this!
Best of luck OP!