Any London writing workshops worth it?

I have a question regarding writer's workshops in London and would be interested to hear the experience of anyone that has attended any courses recently.

I have never attended any paid-for writing course before but am now considering it mainly due to the potential for career development within the literary world. I have written for BBC, Channel 4 and various other film and radio projects and would now like to take my literary writing to the next level and publish a book.

I am always interested in learning to improve my writing but most of these courses look a lot lower level than say an MFA. While Im sure the taught aspects of these paid for courses is good the main attraction seems to be that they are run by literary agents such as Curtis Brown or publishers such as Faber&Faber or people "in the business".

While they seem to be more expensive pro rata than an MFA I realise that the contacts you make often overshadow academic factors if you are looking at writing from a purely commercial perspective.

I realise that there can be no guarantee form any of these course providers as to what you may or may not get out of it but I would be interested to hear if anyone thought they were worthwhile from a commercial perspective in developing a writing career?