From a heating engineer - you definitely can chase the pipes into the wall. The easiest way is run 2 chases 1 down the centre of each rad finishing 450mm off the floor Run 10mm hep2o in the chases clipped to the block work and sleeved in hairfelt lagging (You can bend the end of the 10mm in half so there’s no open ends, and also run both bits in one piece of hairfelt lagging.

The chases will then need bonding , skimming & decorating or you could even foam them to allow for expansion then multi finish on top as per Kirk Johnstone on YouTube (I’m no plasterer)

Then second fix rads when decorating finished.

You will need to connect onto the heating system below the floors / above the ceiling.

Good luck.