Sparks, The R551 easily met the type approval sensitivity spec on MF but so too did the Alert! Somebody has previously remarked that with the Alert switched on or off the result was the same. I would leave the Type 1004 reserve receiver on MF and the R551 on HF where it was superb.
Harry I don't recall the R50M having a very stiff band switch and thought the rotating coil turret a great piece of engineering. It had a little drift on HF.