new to road cycling. what essential kit will i need

A big bank balance, an understanding partner and lots of patience.

Have you got a budget you need to stick to, or is cost not a major concern?

You could just ride in the comfiest clothing you currently have for the moment, ni point spending loads of money if somewhere down the line the bike and you fall out.

I still don't own any cycling shorts,bib or trousers. I find as long as my everyday 3/4 shorts fine as they don't have a inseam that rubs on my downstairs area.

What type of bike do you have and what will it's use be? Mudguards (clip on or permanent) are always a good idea

Best shoes and (bib)shorts you can afford are starters and build from there. Track-mitts/gloves are the other essential (never, ever ride without protection for your hands) but fine to go for affordable mitts.

Shoes will depend on the pedals you have chosen. Go for highest quality insert you can manage in your shorts. Nothing else is "essential" - just add on as you go.

Check it out on wiggle: go for their own dhb brand for inexpensive but good kit. Mudguards are good for those rainy days. It depends on when you will be riding as to whether you need mudguards and lights. If you are planning on commuting then you will need those and some good ones!
You won't need bags unless you are commuting or going for long rides (touring). Get the clothes right or you will be cold as these days get darker.

What sort of riding are you doing, anyway? Typical weekly training mileage?

Bike for starters!

What do you mean by "kit?"