Not from the UK so I'll leave the first question alone.
Don't be tricked into the i5 or i7 categorisation. You have to check the specific model against various benchmarks. A strong i5 might be more powerful than a weak i7.
For a gamer and/or editing computer, you might want to consider:
- A strong graphics card
- A mixture of SSD and HDD for your storage system (SSD for fast loading time, HDD for storage)