Worcester Greenstar Junior 28I Fast flashing blue light fault?

Hi, can anyone help me? our Worcester Greenstar Junior 28I has just stopped working, its not the condensing pipe as that is clear and the weather hasn't been cold enough for it to freeze. I am getting a fast flashing blue light no other lights just the blue one.

Also there is a small leek coming from the top of the burner which had pooled at the bottom and soaked the gas value terminals. So I have completely dried it all out and turned it back on and the same thing happens, it does go through its normal start up cycle but then the light starts flashing and nothing happens.

I have reset it many times and I have tried every thing I can think of but nothing is working.

Is there anyone who has had the same problem and might be able to help?

Many thanks.