I am not sure about their web server. But, I follow the following approach: I have installed the tool in my local computer and then run the tool using Python multiprocessing for n number of protein sequences.

You can download the stand-alone program from here: http://bioinf.cs.ucl.ac.uk/software_downloads/

or from github:

https://github.com/psipred/psipred

Otherwise, you can give a try to the recently released Brewery (which appears to be more accurate):

webserver http://distilldeep.ucd.ie/brewery/;

github http://distilldeep.ucd.ie/brewery/.

Disclaimer: I am one of the authors.