Hi there, yes you can write to the tribunal to point out that the respondent has failed to follow their orders and answer that specific question. Eventually you could apply to the tribunal for an unless order, which basically says that unless they provide the response, something will happen, such as their case will be struck out. This is quite a serious outcome so it is not ordered lightly but it can be a useful tool if there are important failures by the respondent. I would say as a first try you should simply write to the respondent and remind them that they had a deadline, which they have missed and to reply ASAP. Tell them that you will send a copy of your letter to the tribunal and do so. This gives them a kick up the backside and serves as an initial warning. If they still do not reply within a week or two, then you can write formally to the tribunal, copying the respondent, saying that you would like to bring to their attention their failure to reply and that you will next be seeking an unless order if no reply comes within a set date. Finally, as a last resort you van seek the unless order further down the line.
I hope this has answered your query. I would be grateful if you could please take a second to leave a positive rating (3, 4 or 5 stars) as that is an important part of our process and recognises the time I have spent assisting you. If you need me to clarify anything before you go - please get back to me on here and I will assist further as best as I can. Thank you