Anyway, here are a few rates I know people get for certain jobs. Obviously these only reflect a small minority in the industry but I think they are fairly accurate.
SE (206) daily rate:- £250-£300+expenses
ME (355/109) daily rate:- £300-£350+expenses
ME IR (355/109) daily rate:- £350+ plus expenses (negotiate rate)
R22 Instructors are now beginning to get paid £50/hr. About bloody time too.
If you want to accept a 'half day' rate that's up to you but I can pretty much guarantee you'll be selling yourself short. Normally, I believe you would get £50/hr for say, pleasure flying in a 206 up to a max of about 5 hours then anything over that time, the employer would get you for free. It all depends on who you work for and how they treat their staff. I was lucky to work for someone who paid well on a daily rate with expenses and no questions, even if I was stuck on the ground due wx.
Others will have different figures I expect.