did you start them from corms yourself, and if so, when?

What do you mean by "Tichy"? That's not in my vocabulary. If you mean leggy, it's most likely too much fertilizer or the wrong kind of fertilizer.

tichy means small over hear Bathgate.
are they in similar positions to each other. do they get the same amount of water/sun etc. are they in similar sized containers? Do you feed them and if yes with what?
sorry about all the questions but all these factors will determine the outcome for the plant.

Seaburngirl: Thanks for clarification. That makes a big difference. Begonias can't take direct sun, only dappled sun or morning/evening sun. A photo would be very helpful in this case rather then trying to guess.

Corns planted last week of June. Most are sheltered outdoors in semi shade against a wall or by a hedge. In doors east facing or south window. Some leaves are spectacular. One flower so far is 1 cm long.

Other different begonias are flowering in hanging baskets.

Ah well, there's the problem - last week of June is very late to start these off, its more usual to start them into growth indoors or in the greenhouse in April. You may yet get a display towards the end of August onwards.

I find they are one of the most frustrating things to get going. They seem to sit in the pots for ages even in a warm conservatory before they show signs of growing.