If your problem is not straightforward, your solicitor will probably advise you to get "counsel's opinion". This is like going to the GP when you can go straight to the consultant – and paying for both.
Barristers' hourly rates are likely to be lower than those of solicitors of comparable experience and standing. Going straight to counsel for advice will save you money and you will have the benefit of a barrister on your case from the outset.
Wherever possible, I will quote you a fixed fee for the work I do so you will know exactly what the cost will be. However, sometimes this is not possible; for example, because there are a lot of papers to read and it is difficult to say how long that will take. In such cases I will quote you an hourly rate and give a rough estimate of how long I think the work will take. I will keep you advised of anything that changes that estimate.