My working day consists of 6 hours of client work and 2 hours of admin (bookkeeping, marketing, posting on Twitter, etc). Any estimates I give are usually based around one day (i.e. 6-hour) blocks, taking into account the complexity and uncertainty of the work.

Day rate
£40.00 p/hour
Day rate [5+ days]
£36.67 p/hour
Day retainer*
£33.33 p/hour
Half day
£43.33 p/hour

*Paid in advance monthly
**Minimum 1 hour