Receiving and paying parties alike would be well advised to read Gordon Exall's blog which refers to CPR 46.9 and the Solicitors' Act 1974 and their relevance to inter partes costs. Click on the link below:

https://civillitigationbrief.wordpress.com/2016/06/13/overspending-on-your-costs-budget-better-tell-your-client/

Many thanks, Gordon.