If you issue a gross sum bill, can the client then request a further detailed breakdown?

1. Non-contentious: the client can ask for a remuneration certificate, but that will not oblige the solicitor to provide a further detailed breakdown of the bill. Note that you can provide a further breakdown and make a charge for it, so you should put that to the client and get his or her consent before incurring that additional cost.
2. Contentious:the client can request a detailed breakdown of costs in place of the original bill within three months of receiving it. However, the catch is that this request by the client will then cancel your original gross sum bill (ie if you then decide, when going through the file, that you did not include all your costs, then you are entitled to draw up a bill for a larger amount). Note that this does not apply if you have issued proceedings for payment of the bill, or if there is a Contentious Business Agreement.

Source: Guide to Good Practice (Law Society Publishing; £39.95). A comprehensive guide.