Advice needed for lead tracking

Hello,

I need some advice please.

I provide business support services via my website https://www.virtualofficeheroes.co.uk. Each new client has to request a quote and sign some forms etc before the job is taken on. Therefore sales are not made through a shopping cart. It is a manual process.

I need an affiliate program that allows me to track the leads (sent from affiliates) who complete an online quote request form and which then allows me to manually assign the value of the client spend to the relevant affiliate.

Does anyone know of a plugin that allows me to do this?