The HDMI digital audio signal is transmitted as a single aggregated digital stream that contains a variable number of digital channels (from 2 to 7.1 and even more).
Also in the pre-HDMI days the DVD's SD multichannel digital audio stream was transferred using a single coaxial cable (electrical) or a single optical cable, hence no separated cables for every channel.
Therefore digital channels have to be previously decoded and separated, and then converted by DACs to discrete analog signals.
No hope then to directly get from HDMI a couple of stereo analog signals to feed your stereo amplifier, you should have read all the negative user reviews of that cable on Amazon UK.
My suggestion: buy a cheap (or used) AV receiver with HDMI inputs/outputs and then connect its analog stereo monitor output to the TV auxiliary audio input (red/white RCAs or 3.5mm connector), or just use a couple of speakers connected to the AV receiver.