DaveMP and others have posted extensively on Chung Viet (http://chowhound.chow.com/topics/684407); adding more on the other places on Deptford High Street:
• Quan Viet (on a side street next to the pub close to Evelyn Road)
The slices of fish with dill was very good - served in a pan on a portable stove, already sauteed with some dill and julienned green onion. Comes with a plate with sliced chilli, more frilly dill and green onion to add to the pan for table cooking, as well as peanuts, and a salty, savoury, pungent fish sauce base dipping sauce. A great combination of flavours in this dish from Hanoi: the soft herb flavour from dill, the sweetness sharper green onion, all meshing nicely with the peanuts and dipping sauce to enhance the fish. Also served with rice vermicelli.
Banh cuon were soft rice sheets , fairly well textured, slightly chewy, nicely glossed so that they didn't stick to each other, were filled with little bits of minced pork and black fungus (wished for a more substantial filling). Topped with a little bit of crispy shallots (wished there was more) and three slices of cha lua, a steamed pate with a firm snappy bite. Not bad but I like the ones at Cafe East or Leong Kee more.
Cha chien, the fried pork sausage, was good - nice porky flavour, crisp but not oily skin.
The latter 2 were served with julienned lettuce and coriander, but no obvious sign of the other vietnamese herbs (e.g. shiso).
Sweet obliging service; there's an all Vietnamese menu that the offered to help translate. The fish was compelling enough to make me think that this place warrant further exploration, especially the untranslated menu.
• Westlake aka Ho Tay Quan
Pleasant cha gio (spring rolls) with a good blistery reddish prawn flavoured skin, and filled with savoury bits of minced pork, mung bean vermicelli, black fungus etc. But Chung Viet's version is really better by virtue of being more generous with the pork filling, and by including julienned Vietnamese shiso in their chopped lettuce/coriander to enhance the meaty flavours.
Little rolls of pork in betel leaves were also pleasantly seasoned and given a complex herbal flavour from the betel leaves. Served with rice vermicelli.
Not bad on the whole, but not as good as Chung Viet. They seem to have a friday special of some sort of offal soup.
• Cafe @ Migos
The cha gio/spring rolls here were smaller rolls (but more of them) with the smooth standard cantonese type skin, and a porky filling with a nice pungency probably from fish sauce.
It seems to be the only place on the street that serves rice plates including a popular one with grilled pork, pork skin with toasted rice for a sandy texture, fried egg and cucumber, enlivened with splashes of nuoc cham, the sweet dipping sauce. Not bad.
Most of the tables were having various forms of hot pot, and they have special version that require advance orders e.g. a duck one for £60 that should probably serve 3-4. Easy to think that hot pots might be where the action is; definitely worth checking out.
• VIet Rest
The Cha Gio is very similar to Westlake's version, down to the prawn flavoured skins.
Had a soup noodle with a fettucine like wheat noodle, firm and dark olive in colour. A savoury enough soup with eggy bit of crab, as well as pork in betel leaves, and pieces of napa cabbage and mustard green. In the good not great category.
More soupy noodle dishes on their menu, perhaps this is the part worth exploring on their menu.
On the whole I had the impression that these places were a notch up from Kingsland Road in general, although we'll need to draw from a bigger sample. I think these Vietnamese places warrant more exploration as they've been more promising than the ones on Kingsland Road.
To summarise, I probably had my best meal at Chung Viet, but Quan Viet was also very close, and I had ordered different dishes. For further chowhounding, the hot pots at Cafe @ Migos are definitely worth exploring. Will probably start on the African places next.