Thanks for taking time to reply Marco, it's appreciated.
I've reduced the timeout as suggested and also it would appear the serial.begin command was causing an issue. All works now, well, sort of ;-)......
Is there a way that you know of to keep the LEDs flashing whilst the Arduino performs another function.
At the moment when the pulseIn command is between the preset values and it goes off and calls another command, obviously this stops the LED pattern.
It's essentially an IR remote for a Sony Camera on a drone helicopter. So I want the LED pattern to continue whilst the camera functions are being actioned.
Do you know of a way I can achieve this?
I can post the entire code if necessary, but its just a small sequence to flash an IR LED at different rates depending on what is being called.
Thank you again for your help 