On 30 October 2026 we asked ChatGPT, Gemini, Perplexity and Google's AI Overview the same three questions a homeowner might ask when looking for a party wall surveyor in Cambridge. Each question went to each tool twice, 24 recordings in all. One AI Overview attempt came back with no overview, which left 23 answers.
At least 18 different firms were named across those answers. Most appeared in three answers or fewer. Six firms appeared far more often, and five of them were named by every one of the four AIs. The answers are real; below, each firm's name has been swapped for a letter.
The firms that came up most
Number of answers naming each firm, by AI tool:
| Firm | ChatGPT (of 6) | Gemini (of 6) | AI Overview (of 5) | Perplexity (of 6) | Total (of 23) |
|---|---|---|---|---|---|
| Firm A | 5 | 6 | 3 | 4 | 18 |
| Firm B | 5 | 2 | 1 | 6 | 14 |
| Firm C | 3 | 4 | 1 | 6 | 14 |
| Firm D | 5 | 5 | 2 | 2 | 14 |
| Firm E | 2 | 4 | 3 | 2 | 11 |
| Firm F | 5 | 5 | 0 | 0 | 10 |
Firm A was named in 18 of the 23 answers, including every Gemini answer. Firms A to E were each named by all four AIs. Firm F was named in 10 of the 12 ChatGPT and Gemini answers, but never by Perplexity or the AI Overview. No other firm appeared in more than three answers.
How steady were the answers?
Perplexity gave exactly the same shortlist both times, for all three questions. Google's AI Overview changed the most. On the two questions it answered twice, the second answer shared no firm with the first; in one case, five firms were replaced by four entirely different ones. ChatGPT and Gemini sat between the two.
Reading this as a firm
In Cambridge the AIs largely agreed on a short list. A firm outside that list was rarely named by any of them. A single AI Overview check, though, could give quite a different picture from the next one.
Limits
One day, one town, four AI tools and 23 answers, and AI answers shift over time. Every letter is a real practice from the recordings. Names are withheld here because the point is the pattern across the answers rather than any single practice.
Recorded by What The AI Said, 30 October 2026.