This app was mentioned in 5 comments, with an average of 2.40 upvotes
You don't need permission if you have something that is fitted internally and points out of your window, but if you live in a rented property you might need your landlord's permission as it will be drilled into your property.
Guidance on using domestic CCTV here: https://www.gov.uk/government/publications/domestic-cctv-using-cctv-systems-on-your-property/domestic-cctv-using-cctv-systems-on-your-property
If you have an old phone lying about you could consider using Manything: https://play.google.com/store/apps/details?id=com.manything.manythingviewer&hl=en_GB
It's an app you install on an old mobile phone which turns it into a motion activated CCTV camera, suitable for daytime use (or when there is streetlighting) only. I use it to cover my house when I go on holiday. It's about £4 a month.
That could be a good immediate measure until you get an Argos system installed.
Ai putea sa-ti instalezi Manything pe smartphone-ul ieftin (sau oricare alta aplicatie de surveillance de pe Play Store), sa-l montezi undeva (bagat in priza, of course). Sa nu uiti sa-l setezi sa nu i se blocheze screen-ul though, Android-ul are obiceiul prost sa dea sleep la aplicatii daca nu sunt folosite o perioada mai lunga (i.e. screen locked). Eventual, sa-i dai si brightness-ul la minim odata ce te-ai asigurat ca functioneaza cum trebuie (helps with overheating, sa nu te trezesti cu vreo surpriza, ca-ti ia foc casa sau ceva). Din cate stiu, nu ai optiuni de surveillance pe TeamViewer.
When you get Wifi, try installing Manything on the Xperia and on your own device. The app is pretty self explanatory, you set the Xperia as a camera and your own as a viewer. The app can notify you when there is activity and records streams to the cloud. There's alternatives out there also, but I use this setup with a few old devices at home and it does the job.
You can set up an old phone and use an app like Manything.
I'm sure there's a bunch of different ones but I've used this one for years and have multiple cameras.
Google Play: https://play.google.com/store/apps/details?id=com.manything.manythingviewer&hl=en_US
App Store: https://itunes.apple.com/us/app/manything/id639672976