Just in case anyone's interested...

As a aside, here are the forces taking part as of Turn 1 of 40.

(A) World Eaters ()
(B) Deathskulls ()
(C) 23rd Callien Mechanised Infantry Brigade ()
(D) 13th Company ()
(E) Feral Orks ()
(F) Blood Angels ()
(G) Iron Warriors ()
(H) Dark Eldar Wych Cult ()
(I) Sisters of Battle ()
(J) Relictors/Radical Daemonhunter ()
(K) Goffs ()
(L) 17th Calin Drop Regiment ()
(M) Biel-Tan Craftworld Eldar ()
(N) White Scars ()
(O) Feral Orks ()
(P) Lost and the Damned ()
(Q) Tau ()
(R) Tyrannids ()
(S) 15th Vanheim Recon ()
(T) Ulthwe Strike Force ()
(U) Thousand Sons ()
(V) Kroot Mercenaries ()
(W) Dark Angels ()

The decision of where people entered the city was random (23 letters were put on sheets of papper and everyone taking part picked one). The players were using hidden movement on the map (it's a pain in the ass for me to keep track of but it makes things interesting).

TURN ONE
All of the forces taking part in the campaign made moves into the city. Early highlights include.

The World Eaters and the Dark Angels clashed within the old Cartel House dwellings, a bloody conflict (I was not there but from what I heard there was less than a dozen miniatures on table by the end) won by the forces of chaos.
The Blood Angels and Iron Warriors clashed when the chaos forces attacked the Imperial's starting point while heading for the Spaceport, the Iron Warriors were beaten back.
While the 17th Calin Drop Regiment entered the Railhead Terminus, en route to the 122nd Cadian HQ the Goff Orks attacked the rear of the Calin lines, an attack repulsed by the Imperial rearguard.
A pitched battle between a Tyrannid hive swarm and the 15th Vanheim Recon Regiment at the Water Purification Plant. The Hive Mind swamped and destroyed the Imperial recon force.
At the Trading Houses to the north of the city, a mercenary Kroot force attacked a Thousand Sons force, and was wiped out by the Chaos force.
As the moderator I got my first game of the campaign, playing the defense forces at the Arbites Precinct House against a Ulthwe Strike Force (using one of the other players Cadian army). I went top-heavy on Heavy weapons and managed to beat off the xenos for a turn.

TURN TWO
A whole lot more action this turn as the situation started to get interesting.

• The Dealer's Accomodation saw battle between the Thousand Sons and Deathskulls Orks. The Ork force took the area.
• The Trading Houses also saw action between the Thousand Sons and the Kroot mercenaries. The Kroot drove off the Chaos force.
• The Arbites Precinct House was the site of a three-way battle between the soldiers of the 15th Vanheim Recon, the Ulthwe Eldar and (my) Arbites Defence Force. After a somewhat imbalanced battle the Ulthwe were driven off and the 15th claimed the Precinct House as a HQ within the beseiged city.
• In a somewhat one-sided battle between the Tau and the Tyrannid horde a exceptionally jammy Biovore shot killed the Tau's ethereal in turn one :O and most of the army made a immediate tactical withdrawal (or, in other words, ran away ). Suffice it to say, the Hive Mind gained more territory.
• In a rematch of last turn, the World Eaters and Dark Angels fought over the Cartel House Dwellings. The Dark Angels driving the Chaos hordes from the area (and cutting them off from their starting point).
• The World Eaters also attacked the Deathskulls Orks between the Cartel House Dwellings and the Vogen Theatre House. In a run of spectacular bad luck the World Eaters were driven off by the Ork horde.
• The Iron Warriors claimed ground from the rearguard of the Blood Angels army while the sons of Sanguinarius moved into the Spaceport Complex, which also appears to be the destination of the Feral Orks located to the north of the city (who now hold the Imperial Senate House).
• The Relictors army (assisted by a very, very radical Daemonhunter Inquisitor) came under attack from a Goff horde. Mostly thanks to the three Daemonhosts the Inquisitor provided, the Orks were driven off).
• The White Scars and the Biel-Tan ran into each other outside of the 122nd Cadian HQ (or should that be, in the case of the White Scars, ran over the Biel-Tan), the xenos retreated after suffering heavy losses.

As of the end of turn two, the standings are as follows.
(A) World Eaters (0)
(B) Deathskulls (3, Dealers Accomodation)
(C) 23rd Callien Mechanised Infantry Brigade (6, North Road Gate, Vogen Theatre House)
(D) 13th Company (4, Half of the Palace Grounds)
(E) Feral Orks (3, Half of the Mercantile & Pleasure District, Imperial Senate House)
(F) Blood Angels (2, Spaceport Complex and Generatorium)
(G) Iron Warriors (0)
(H) Dark Eldar Wych Cult (2, Habs Beta and Gamma)
(I) Sisters of Battle (2, Habs Alpha and Delta)
(J) Relictors/Radical Daemonhunter (4, Building 235)
(K) Goffs (0)
(L) 17th Calin Drop Regiment (4, Railhead Terminus and 122nd Cadian HQ)
(M) Biel-Tan Craftworld Eldar (6, Railhead Depots and Basilica Imperialis)
(N) White Scars (0)
(O) Feral Orks (2, The Eastern set of guns)
(P) Lost and the Damned (5, the Vogen Law Courts)
(Q) Tau (2, Execution Square)
(R) Tyrannids (2, Water Purification Plant, Administrative Quarter)
(S) 15th Vanheim Recon (4, Arbites Precinct House)
(T) Ulthwe Strike Force (0)
(U) Thousand Sons (0)
(V) Kroot Mercenaries (2, Trading Houses)
(W) Dark Angels (1, Cartel House Dwellings)