G-ARVE since you are departing on Tuesday, Thursday or Saturday (dates would have been helpful) you qualify for STPC. You do not qualify for +Qatar since your transit is under 12 hours. That said the rules for +Qatar seem to be interpreted in a very relaxed fashion so you may get lucky!
Sorry there was a typo in a link in my previous post which removed important parts of the post. It is now corrected. There was a link to the list of visa free countries, which includes UK.