Clash of the Metal Titans

The first four series of the iconic robotic combat gameshow Robot Wars were a straightforward knockout tournament: each episode comprised a single heat, the winner of which would progress to a semi-final, and the winners of those would progress to the Grand Final. Thus, the episode titles for those series followed logically: "Series 2 Heat K" or "Series 3 Semi-Final A" make it clear what you're talking about.

But after the Fourth Wars, the UK championship took a temporary backseat for Robot Wars Extreme, a series featuring a wide range of different mini-tournaments. Each episode of Extreme 1 featured a mix of the different ongoing tournaments, plus the occasional one-off battle. So with the exception of the two Annihilators (which featured six robots who qualified from the earlier "Mayhem" melees fighting together, with one robot being eliminated each round until only one survived), and the Second World Championship, those episodes don't have any easily identifiable moniker.

Except the original Radio Times listings appear to have given each episode a title. One fight in each episode would be branded the "Main Event" of the night, and most of these titles come from those: I don't know if these were official titles given to them by the production team, or if the RT made them up themselves. At any rate, the episodes were titled thusly (read this list alongside the Robot Wars Wiki's episode guide if you like):

1. The Challenge Belt
2. The Ultimate Mayhem
3. The International Inferno
4. The Ultimate Vengeance
5. The Armed Forces Mayhem
6. The Ultimate Vengeance
7. The Annihilator Special
8. The Ultimate All-Star Conflict
9. The House Robot Rebellion
10. The Second World Championship [NOTE: Shown in this position on BBC Two, but had aired as Episode 16 of the earlier BBC Choice run]
11. The Forces Special [NOTE: Shown in this position on BBC Two, but had aired as Episode 17 of the earlier BBC Choice run]
12. The All-Star Quarter-Finals
13. The Flipper Frenzy
14. The All-Star Semi-Finals
15. The Tag Team Terror Final
16. The Annihilator Special
17. The All-Star Grand Final

Given there are two different fights dubbed "The Ultimate Vengeance", the two Annihilators are not differentiated between, and one of the twelve Mayhems has seemingly been arbitrarily given the title "The Ultimate Mayhem" just because it had Hypno-Disc in it, these titles are sadly not terribly helpful. Still, the Radio Times listings are the only place I've ever seen these episodes referred to as anything other than "Episode 1", "Episode 2", etc.