Samsung RL38 leaking

Hi, I have a Samsung RL38SCPS fridge/freezer that is leaking from the bottom of the freezer section (located under the fridge). There was a build up of ice which I scraped off, but more has formed in the last couple of days. From research I’ve done, the problem is likely to be the drain being blocked, so the water can’t get to the condensor to the rear of the unit. I have just tried switching it off, removing the freezer trays, and then removed the back panel. However, I then came across another panel, grey in colour, unscrewed the 2 screws but the panel doesn’t want to come off (picture attached). I’m guessing it’s frozen on and didn’t want to force it off. Also guessing that behind this panel I’ll be able to access the duct that may be blocked, stopping the water draining. Can’t find a service manual for this model anywhere! Any advice would be greatly appreciated!