1. I regret to say that your solicitor is treating you as a "cash cow" and taking excessive fees from. Essentially, it should not have cost 23k to date given the simplicity of the issues involved in the divorce. Nor should it cost another 20k to finalise the divorce given the agreement yourself and your wife have. Accordingly, I would advise you firstly, to get yourself another and cheaper solicitor immediately, and secondly, to make a complaint to the Legal Ombudsman concerning the extent and level of fees which you have been charged to date. Essentially, a client can change solicitor at any stage if he is not happy with the service being provided. This includes in family law proceedings such as divorce. The new solicitor will have to give the old solicitor an undertaking that his fees will be discharged to take up the legal case file. However, this does not prevent you making a complaint to the Legal OMbudsman about the fees you have already been charged or will be charged.
2. You can also represent yourself at this stage if you so wish. The issues are not very complex so if you know the parameters of divorce, you can always represent yourself.