Baz wrote:
We have just finished erecting a greenhouse and would like to know whether

Funny time of year!

to pave it or use the soil it is already on to grow tomatoes.

I would suggest concrete/pave, then use grow bags. Otherwise you will end
up with a build up of soil that isn't being rotated with other crops. (Our
grow bags then get thrown onto the garden beds)

But there are advantages to both, as with everything.