Business contract to be checked and amended

We are new internet start up, we help people with unused
space in their house rent this out to people looking for cheap storage. The
site matches up both sides and helps people put in place their storage
arrangements. We give people a downloadable contract they can use.

However we need for this to be checked and amended so it is fit for purpose. We have an investor who is interested in helping our tiny company but needs some evidence from a legal expert to say that the contract is fit for purpose. We need a really quick turn around, by Tuesday 2 April (latest)