I will be assisting you today.
You first need to write to the Defendant requesting payment, failing which you will take them to the Small Claims Court. This letter is called a "Letter before Action". Please see the attached that has a template Letter before Action
The letter need to amending accordingly.
As your claim is worth less than £10,000, then it must be issued in the Small Claims.
To Issue at Court, you need to complete a Form N1 together with the appropriate Court Fee. The Court Fee would be based on the value of the Claim.
There is nothing stopping you from Issuing the Claim yourself.
I also attach herewith a link that will assist you in issuing the claim should you wish to do this yourself:- www.gov.uk/make-court-claim-for-money
As stated, you can issue the claim either in a paper and at your local court or you can do the claim online via MCOL, the attached link above will explain how it all works.
If, however you are more comfortable with a solicitor to deal with this on your behalf, then you need to seek the services of a "litigation solicitor", a quick search of this term, in your Internet browser should reveal a number of local solicitors. Although not necessary, I would advise a personal appointment, hence, why a local solicitor is ideal, to allow you to see the solicitor in person and to explain all the intricacies of your case. I would ask for a free interview with your local solicitor and also to see if they are prepared to work on a "fixed fee basis" to help you. Fixed Fees we will at least give you certainty in terms of cost and also allow you to budget for the litigation.
As your case is valued under £10,000, then please be advised that neither party is entitled to recover their Solicitor's costs if they use a solicitor, no matter if they win or lose. In the small claims court, you are entitled only to your issue fee together with some expenses.
I hope this assists. I would be greatful if you could accept this answer and provide a 5 star rating at the top of your screen so that I may be credited for my time.
All the best.