It is not only avast, eset also has the site blacklisted: https://sitecheck.sucuri.net/results/www.thetirrellroom.com

There is a hidden iFrame:
The link: -http://www.googletagmanager.com/ns.html?id=GTM-WQKPPS is blocked in browsers by script blockers.
as is this script: -http://dnn506yrbagrg.cloudfront.net/pages/scripts/0025/9827.js

Also please check this list for unknown links on the website:

-http://www.abingtonalehouse.com/ → ‘’
-http://www.thecharliehorse.com/ → ‘’
-http://www.plymouthbaycatering.com/index.cfm → ‘’
-http://www.bhmansion.com/ → ‘’

When the website indeed is non-malicious, the only ones that can unblock is an Avast Team Member.
We here are not, just volunteers with relevant knowledge.

Wait for an Avast Team Member here to give the final verdict and eventually unblock…

For IP also consider: https://www.threatcrowd.org/ip.php?ip=172.99.94.187

polonus (volunteer website security analyst and website error-hunter)