Ok lots of info from friend. I'll just copy and paste it here Rich.
The camera birdbox we got is now nearly 2 years old, and at that time quite a new gadget, it was about £130.
They have now become more common and considerable cheaper. The camera set up is not complicated and can be purchased from any electronics shop for between 20 and 30 quid. add £20 for a bird box and becomes a little bit more affordable I have also sent some links to sites.
Most nest boxes are simply designed and have a hole in the front. This should be a different size depending on the type of bird you're trying to attract. They can be made or bought Blue tits, coal tits and marsh tits: make or buy a box with a small hole, approximately 25mm across. Great tits, nuthatches, house sparrows and tree sparrows: put up a box with a slightly bigger hole, approximately 32mm across. Robins, wrens and pied wagtails: these species prefer open-fronted boxes but these can be vulnerable to attack by cats so make sure you put them somewhere safe. Starlings: boxes for starlings need to be long with a hole near the roof. Place them high on walls as starlings sometimes nest in roofs or in the walls of dilapidated buildings. Sparrows: gregarious birds such as sparrows nest close to each other in communal boxes, sometimes called terraces. This box has three compartments with a hole just under the lid at each side and in the centre. They may also nest naturally in the roofs of your house.
Site nest boxes so that they are sheltered from the wind, rain and strong sunlight. If they are in full sun, the chicks could overheat and die. usually facing north Position boxes 1.5-5m above ground for safety from predators and to replicate natural nesting habits. It's best to put nest boxes up outside the breeding season, between August and February.
Lidl or Aldi were selling a complete kit, box camera and receiver for about 30 quid
Links:
HandyKam.
Wireless Pinhole Spy Camera.