I hope it is your pure business decision to choose writers from the UK only. However, I would like to advise you that there are many competent writers based in other parts of the world. And I am one of them. Please let me know as we are filtered.
Its pure business. I need people that know first hand about the UK solar industry
The Case Study is a short task that is a taste of what the full Job will be like and
gives you the opportunity to show the Buyers your skills.
Keep in mind that you have more chances to win a Job with Case Study as fewer Sellers will send a proposal.
Moreover the Buyer has already paid a fee for it, which shows that they seriously intend to award the Job.