Here are some suggested miniDV camcorders.

Under £250
At under £200 Canon's MD110 is probably the cheapest minDV camcorder with a microphone socket. They aren't particulary robust. You might be better going for the Sony DCR-HC45E which seems more solidly built. Controls on both these cameras are a bit fiddly, particularly the buttons next to or on the screen.

Under £400
Best deal at the moment is probably the Panasonic NV-GS230 for £300 including VAT online. Be careful where you buy it from, though - some of the internet dealers stocking it don't get good seller reviews.

It appears to be an NV-GS250 without the DV in - we have one of those and it's an excellent little camera. It has a microphone socket, unlike the more recent NV-GS320 (though that does have DV in).

Panasonic's joystick control, and the ease with which you can accidentally switch modes, are slight drawbacks, but apart from that these are very nice cameras to use.

Under £600
If you have a bigger budget you might consider the Canon HV20. This is a high definition camera which will also shoot in standard definition, and it has all the sockets you need for around £550.