Locked rear wheels

Hi all!

UPDATE: Just went back out to give it another try. Same passerby was there - they said they made a mistake and it had been only one of the wheels that was stuck. This prompted me to be a little less gentle on the accelerator, since it was likely just a rusted drum brake. Indeed, 15 seconds of forward and back eventually led to a "pop" and the wheel was free.

Does anyone have suggestions for servicing the rear drum brakes to prevent this from happening? Perhaps opening them up and spraying the non-braking surfaces with a penetrating oil or something?

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Another problem with my 2008. Went outside this morning to drive to work. As I started to pull away, I noticed that the wheels felt "stuck" in place. Not that unusual - I find this happens slightly sometimes after rain when the car has been sitting, and a gentle application of power unbinds them. (I always apply the parking brake when parked - a holdover from learning to drive in the UK.)

Not so this morning. Usual amount of accelerator did not cause any movement. I continued pressing until the car started dragging itself forward. After a good 10 ft of the stuck feeling still being there, I stopped. Lowering the window and reversing, I saw that the rear wheels were completely locked in place. A passerby confirmed that it is both rear wheels. The car has been parked since Thursday 30th July.

Rocking the car back and forwards, manually or using drive/reverse has done nothing to free the wheels.

One thing I've noticed - the parking brake pedal feels quite a bit more taught / tight than usual. It's usually relatively slack (at least compared to my wife's 2006). I hope this might point to the problem.

From reading a few threads on here, the suspects are: stuck pads on the rear disk brakes or a stuck parking brake cable.

Does anyone have a sense which is most likely given that both wheels are stuck and the newly tight parking brake pedal? That sounds like the cable to me, but I'm not sure if there are other things to check.

If it is the cable, does anyone have a link to a video / write-up of how to service it? Or should I just call a garage now and get it towed?

Many thanks in advance for your always useful advice!