My memory is letting me down so I would be grateful if someone would confirm whether the Murena front discs are the same as the ones for a Talbot Alpine / Solara
Not necessarily. There is more than one size fitted.
The part number you want for the front discs of a Murena (1.6 or 2.2) are 17740314 for a single one. However they were often sold as a pair and also the later numbers changed to a 6 digit number originally with a full stop after 4 but later they forgot the dot and just quoted 6 digits. The discs should be 240mm dia. (239.7mm to be exact) and 11mm thick. Some of the ones you see listed are a slightly smaller diameter, e.g. 237mm and since the more material the better for absorbing the heat and these are fronts which do more work, you want the correct size preferably.
I have one plain pair of originals left or there are the Simon discs which are grooved and crossed drilled but obviously a bit more expensive.
You can't have vented discs as 11mm thick is not enough to have this, so Simons discs give a sort of 'half way house'.
Roy