Right, I'll try and list off the things I'm looking for, hoping someone can give me an option that incorporates all of them..

1) Live TV that can be paused and rewound; not too fussed about amount of channels as we only watch about 30, but don't want to completely lose the regular channel hopping experience.
2) Catch up TV to watch things we've missed
3) Streaming from computer; I download stuff on my Mac, that I'd like to stream to the TV rather than needing to copy it to pendrive as I do now; if possible, an app that allows me to stream things to my iPad, PS3 or Lenovo tablet (from the Mac) too?

If I can achieve these things with a box (freeview+ box?) and a dongle (chromecast or similar?) then that would be ok, but I'd rather use as minimal amount of different technologies as possible; my wife isn't amazing with technology so I do like to keep it simple.

a Freeview PVR will do all that you are after.

If you have BT for your phone then a YouView box would be an option.

I have a Humax FreeSAT box but I guess they are the same once the signal gets inside it. A very clever feature is being able to go backwards through the planner to see something that was on up to a week before as well as being able to stream PC/Mac content to it.

Like these

http://www.techradar.com/news/video/...-the-uk-718172

Hmmmm. Was hoping for something south of the £100 mark if possible? How are each of these for streaming from Mac? I'm conscious there may be compatibility options as Apple tend to be complicated when it comes to third party apps, etc

For less than £100 your best choice is the older Apple TV at about £59. It will enable you to mirror your Mac on to your TV screen. There are no reliable PVRs under £100. If you like taking a risk there is always Cash Convertors or E-bay.