Very small extension costs? Kitchen and bathroom costs?

[Matt..]

I have a small end of terrace house in south Wales that really needs some work doing to it but i'm early in the process so getting quotes from builders would be a struggle i'm sure. My house has an extension out back that is two storey and contains the bathroom and kitchen. It's very old and the same extension was done to all houses in the street. It's old enough to have no cavity and so is very cold. The room is internally approx 2.7m x 2.7m. Kitchen and bathroom would need back to brick renovation and the wonky upper floor fixing.

Can anyone help with approx prices for getting this done so I can know the area it'll approx be in?

1. New bathroom and kitchen in existing structure moving an external door from kitchen to dining room and opening the kitchen to the dining room
2. Very small side run extension of approx 1x3m

My guess for 1 is £30k. I really don't know for 2 as I see wildly different prices all over the internet.

The extent of my ability in this area is designing the basics of a kitchen and bathroom, but pricing the building work and knowing what's realistic there is outside of my knowledge.

Thanks