You can do a Reply to the Defence, but frankly, I would only do so if there is a counterclaim or set off pleaded in the Defence.
Next you will need to submit witness statements. You should include all statements and exhibits of anything you want to say at trial.
Unless you have acted unreasonably, there is no costs award against you on the SC track, apart from witness expenses (and they are limited to travel expenses and loss of earnings of up to �50 per day).
If you are successful, you can't claim your costs, apart from the fixed costs of lodging the claim and your own witness expenses - again this is unless the other side have acted unreasonably.