The problem here is down to conflicting issues.
Conflicting issues I believe that are actively encouraged by the tunnel operators.
(1) Despite promises years ago that the tolls would eventually be removed for the purposes of making the tunnel “free” (so we thought) - they are now only switched to the “congestion charge camera log” system. APNR.
(2) “Traffic flows will be greatly improved” we were told, when concerns were raised over the new extended delays whilst the tolls were demolished.
(3) Now the new toll area is completed, we now see a wall built that has the side effect of committing traffic trying to approach from J1a in particular - to the wrong underheight tunnel, bearing in mind that there are a a few depots within a mile of the tunnel that use double deckers.
(4) “No quarter given” when a driver makes the mistake of using J1a then.
(5) Gantry signs warning that the right hand tunnel is closed are NOT being put up in time as “not to trap northbound overheight traffic” - Especially when this nasty measure of "Shutting the exit at J1a" seems to match those occasions when the “height warning” isn’t being given on gantry signs for miles around.
(6) J31-30 is closed, because there is extensive works going on there. Fair enough, but why can’t we have the approaching bottleneck as the LEFT tunnel closed, assuming that it’s to prevent four lanes going into one on the tunnel exits…?
(7) Blackwall tunnel closures should be suspended when the SOUTHbound approach is congested. Don’t close the bloody main artic escape route for southbound traffic please!
(8) Closing 29-31■■ - Leave the bloody Thurrock roads alone then! - especially that last “on slip” that comes onto the southbound carriageway just before the bridge…
(9) Petrol Tankers - Is it me, or are these drivers increasingly driving in a reckless manner? It must be some severe job and knock infection that they now seem to drive up my arse all the time when I’m trying to traverse roads around the Circus Tavern area…
(10) A406/M11 - DON’T bloody well cone it down to one lane on any nights that a diversion down the A13 is in effect. FFS Traffic jams are a total man-made thing. ThaT doesn’t mean the roadwork planners have to waste as much of every haulier’s fuel budget as possible! I wouldn’t be surprised if we hear of a few yards going ■■■■-up over the inflicted “Dartford Crossing Knock-on Losses” before long. 
M25 closures in general - need more advance warning: That is, on the incident’s actual approach roads and NOT roads that are miles away, and heading in the wrong direction for it. I’m not interested in 15’9" headroom at dartford when I’m going down the M3 towards Southampton, only to find out that J3 at Lightwater is bloody closed off on the Exit Slip! ARRRGH!.