The maker isn't being questioned. According to the seller, this tub-style chair still has the Artofort label and the manufacture date stamped to the frame. They obviously don't know for sure about the person behind it though – we have looked online for one similar and we have also drawn a blank.
Still, a great example of 1950s modernism from a noted maker, with an ebonised beech wood frame and wool upholstery – the sprung seat has its original black and red polka dot spotted wool finish. The grey wool sides is a later replacement material. Note also that the seat material has had a small repair to the front corner (see image on listing) which is hardly noticeable and now professionally repaired.
Overall 'good condition' and selling for £300.