Yes. Most courts have a Witness Service and if you contact them in advance of the case they can arrange for you to look at a courtroom. It may not be the same courtroom that you give evidence in, but they are all very similar.
Visiting the court beforehand can help people feel less intimidated about giving evidence. Knowing where everyone sits in the court room and who they all are can put you at ease.
A link to the Witness Service referral form can be found in the Related Information.