Can see varying estimates for premises in your postcode
35 to 79
25 to 63
27 to 67
30 to 75
20 to 54
This is impacted low figure to clean high figure, it may be that PlusNet just used the clean range which is generally higher.
All in your small road, and based on where the cabinet is and your postcode location those ranges seem sensible, and thus given the work to improve things probably resolved the internal wiring/socket issues another visit is unlikely to do much more.
One speed test in your road, but looks slow due to wifi (on an ipad) and around same distance on same cabinet there is http://www.thinkbroadband.com/speedtest/results.html...
which looks like user on the 38/9.5 capped product.