I have plugged my aerial in the back of the video combi,then connected to TV.
Picture is okay,BUT I cannot record anything.

So is it the aerial or the TV or Combi not being "digital"?

Any help most wellome

The video combi almost certainly is only able to record analogue, so the only way would be to record the current programme on the TV via scart out on the tv.

It may be possible to wake the TV up and get the combi to record what is on the TV if both support this.
ie TV wakes up to channel 101 at 1800
Combi records from scart in at 1800 unitil 1900.
Depends on make and models.

You need to post the exact make and model of the DVD/VCR unit for us to offer any meaningful advice. If we don't know what we are dealing with it is impossible to answer your question properly.