Can you advise the model number of your Baxi boiler?
I would start by checking the overflow pipe on the boiler this should be a plastic pipe which goes under the boiler tape it and it should sound empty, if it sounds full of water you need to see where it goes and clear the blockage.
Are any error codes displayed, and when was the boiler last serviced?
If the overflow pipe is not blocked, you will require a gas safe engineer to attend and strip down the unit, it may be a simple case of flushing through the overflow pipe, and cleaning the chamber, or may be an faulty component, stopping the boiler starting.
If you would like me to recommend a suitable engineer to come to site please provide your postcode.
This sounds like there is a sensor fault with the flame sensing electrode (15 on diagram shown at the top of page 6 here), which is located to the right of the spark electrode.
If this isnt detecting a flame, the PCB will keep calling for a spark, after 10 seconds the safety cut out should kick in at which point it should be generating a error code.
The fact you can hear it sparking, and see a flame I would be reasonably confident its the electrode at fault, as that would certainly be responsible for cutting the gas off after a flame is lit, and tell the PCB to keep calling for a spark.
I havent heard back from you in the last day or so, and just wanted to check if you still require assistance, I would appreciate it if you could rate the service received.
I havent heard back from you in the last day or sp, and just wanted to check if you still require assistance, I would appreciate it if you could rate the service received.