Led bulb in cold water taking minutes to light up - need replacing?

[RL19]

Hi all. I have a cold plunge barrel with an 1W LED bulb in. Water is cold c. 3-5 degrees. Light used to come on instantly but now takes a minute or so then flashes a bit then comes on eventually after about 2 mins. Do you think the delay is the bulb or driver warming up or is it just a sign the bulb needs replacing (big job as need to drain barrel)? It is not old maybe 6 months (but 6 months in cold water). Pic of bulb attached if relevant. Thanks a lot for any views

 

[Geoff1946]

Assuming the driver is separate and accessible just connect a spare lamp to it in place of the one in water. If it works straight away you need to replace the lamp, or the opposite.