You might try asking here...Lots of tomato knowledge at The Tomato Forum.

Sue

Here is a link that might be useful: Growing Tomatoes Forum

What do you mean "fed and watered as required"? The number one reason for big plants and no fruit is too much fertilizer. The number 2 reason is that the plant in question has been consistantly at 90+. Most tomatoes won't set fruit when it is that warm. If possible, get them a little shade in the middle of the day when it's that hot- a shade cloth or row cover works for this.