However, my friend has a neighbour who says they are protected, but to my knowledge they are only protected in Ireland.
Also, where would I stand if one should drop over his boundary, which sometimes does happen in all shooting aspects.
Your friend’s neighbour is technically correct; the collared dove is a protected species. However it is regarded as a pest and may be shot under general licence.
You can view the general licences on the BASC website www.basc.org.uk/en/shooting/general-licences.cfm
They differ slightly depending on whether you live in England, Wales or Scotland and it is important that you read them before resorting to the gun or trap.
Broadly speaking you may shoot collared doves to prevent serious damage to crops or the spread of disease and to preserve public health and public safety.
Before you shoot you will have to satisfy yourself (not the friend’s neighbour) that the birds were causing or likely to cause damage and that shooting was the only practicable option.
A low-power airgun is a good tool for the purposes you outline.
It is an offence to fire a pellet from an airgun if it crosses your boundary unless you have the neighbour’s consent.
All shooting must be done in such a way that the pellet remains on your friend’s land unless you can persuade the neighbour to allow shooting over his land.
If a bird falls dead on the neighbour’s land then it becomes his property.
Ideally you need to come to some arrangement about retrieving it, otherwise it must be left.