Progress so far:

Ran Malwarebytes' Anti-Malware 1.61 - No malicious items detected

Ran the Repair IE8 script ie8-rereg.cmd

Reset IE8 Settings (With Delete Personal Settings)

This has made a small difference and speeded up the loading of web pages but I still get the problem with web pages that contain a large number of items and images although the delay is not as long as it was.