The Roman Map of Britain Londinium Augusta London

Londinium Augusti (R&C 97) next
Londiniou Londinii, gen. (Ptolemy I 15 7)
Londinion Londinium (Ptolemy II 3 12) a polis of the Cantii
Londinio (AI 471₅ Iter II)
a Londinio (AI 473₁ Iter III)
a Londinio (AI 473₆ Iter iv)
a Londinio (AI 474₁ Iter v)
a Londinio (AI 476₇ Iter vi)
Lundinio (AI 477₁₀ Iter vii)
Londinio (AI 478₅ Iter vii)
Londinio (AI 478₆, 479₉ Iter viii)
Lundinio (AI 479₁₁ Iter ix)
Lundinio vars. Lindinio, Londinio (AI 480₈ Iter ix)
Londinium (Tacitus Annals xiv 33)
Londinio (TV 154.9)
Londini (TV 310.back 22)
Oppidum Londiniense (Panegyric viii 17 1)
Civitate Londinensi (Council of Arles)
Lundinium (Ammianus Marcelinus xx 1 3)
ad Lundinium, vetus oppidum quod Augustam posteritas appellavit (Ammianus Marcelinus xxvii 8 7)
ab Augusta profectus, quam veteres appellavere Lundinium (Ammianus Marcelinus xxviii 3 1)
Lindonion Lindonium (Stephanus of Byzantium citing Marcian's Periplus)
LON, LN, L (London mint-mark)
AVG (London mint-mark, coins of 4th century)
Londini ad fanum Isidis (JRS xii (1922) 283 graffito on a 2nd c jug)
Londinio (JRS xliv (1954) 108 address on wooden tablet)
Londinio (JRS l (1960) 108-111 tablet)

    RIB 19, on an early third-century tombstone of a speculator of Leg. II Augusta, taken to be a member of the governor's staff in London.
    [Dis Mani]bus / [Vale]r(ius) L(uci) f(ilius) C[l(audia)] Celsu[s] / [3 s]pec(ulator) leg(ionis) [II A]ug(ustae) An/[to]n(ius) Dardanus Cu[r]/[sor R]ubrius Pudens / [3]s Probus sp[e]c(ulatores) l[eg(ionis) / [

    The Ravenna Cosmography's records Caerleon as Isca Augusta (R&C 52), Chester as Deva Victris (R&C 86), and London as Londinium Augusti (R&C 97). Augusti, properly Augusta, may simply indicate the source of the local contingent - Leg. II Augusta. If so, the honorific title is that of the legion - not the city.

London (TQ3281)

Additional records of Leg II Augusta at London:
RIB 3 Ulpi/us / Silva/nus fac/tus Arau/sione emeri/tus leg(ionis) / II Aug(ustae) /votum / solvit
RIB 17 D(is) M(anibus) / Vivio Marci/ano |(centurioni) leg(ionis) II / Aug(ustae) Ianuaria / Martina coniunx / pientissima posu/it memoriam

See Frere (1987) p 199 for the view that the city was renamed coincident with Constantinius' elevation  from Caesar to Augustus.