Finding help with the 'spec' for the nursery

Although the waiting for solicitors to do their stuff is very frustrating, I have managed to make some small progress with planning the site.  I realise that, as soon as we exchange contracts, we will submit our planning application.  I've checked with Henry and he says this will take about 8 weeks with Christmas adding a week.  But once we get to this stage I need to think positively and assume that we will get the planning approved and that after that I dont want big delay before we start construction work. The vision for the initial nursery  infrastructure is a tad ambitious; most people seem to start with a cheap polytunnel and evolve their site as the business grows. But I dont want to take that approach.  I have looked at many nurseries over the last 5 years as my original plan was to buy a 'going concern'  and have only decided to start from scratch this year. What I have learned from looking at those sites is that it is very hard to get any labour efficiencies if your site is made up of separate polytunnels or  even if you have one larger greenhouse but the internal structures dont allow for adaption.  Therefore, the plan is to assume that this business will take off and achieve the required sales volume to pay me a living wage (I know; I'm dreaming).  Having calculated what that turnover needs to be, I know what scale of infrastructure I will need for that number of plants and can work backwards to try and design this in phases.

Phase 1:  build the first span of the planned 4 spans or greenhouse/multi-span polytunnel but with the automatic watering and ebb-flood trays that you would normally expect in a much bigger operation.

As I do not have a commercial horticultural background, there are some fairly major gaps in my knowledge when it comes to knowing exactly how to define the specifications for groundworks, irrigation and all the cables and pipes I am going to need so I have been looking for a consultant to help me with this.

I might have found someone  who fits the bill, but I'm not sure yet.   The first thing he said when we spoke was that I should put in glass growing houses not plastic. As this was one of the decisions I was most sure about, he really threw me with this. But some of the other things he said made good sense so I will need to speak to him some more and see if we click a bit better.

If anyone reading this has any recommendations I would love to hear from them.