Hi wondering if anyone could share a spread sheet of there costings on a conversion I am happy to make a new one out but I feel like I will miss out essential details and just looking to throughly calculate how much we are possibly going to spend before going for planning permission.

Thanks ?

Quickest way is send off the plans to one of the online estimators and then play with the outputs when you get it. 
 

Without seeing your plans it is impossible to tell you what you may - or may not - miss out as all quantities and materials will be unique to your build. 

I am doing a conversion and found it very difficult to get fixed prices because of the unknowns

It is difficult to estimate...we dont have to pay for the land or the building as it will be gifted by my mother...its a granite steading with slate roof and it's pretty old but the stone work is in good nick...most of the roof is gone but slates have been salvaged "if" they can be reused and my father in law is an experienced stone Mason so he Is happy to help with that in his free time (semi retired) and my cousin is going to draw up some architectural drawings for family rates, and my husband is very handy so anything he can do himself he will like demolition, fitting kitchens, bathroom and decorating...

We have utilities onsite they just need to be connected..

The actual plumbing, electrics, insulation (especially in a granite building) and the actual timber structure inside is a mine field to me ?

 

Any online estimator recommendations?