Tax advise for cross-border worker

General information for the business: Director of freelance consultancy, Ltd company registered and trading in the UK
Legal topic: Tax
Description of legal work: I run a ltd. company in the UK and am a cross-border worker by living in another European Union country. Seeking for help about taxation. Which impact does my cross-border worker status have on my residency status, so I can do my self assessment properly?

Help required particularly with
- interest earned outside of the UK
- interest earned on ISA in the UK (residency status might change things?)
- amount of savings I can transfer from my savings account in the other EU country to my UK savings account without having to declare those savings as another income
- use of home office if there are two home offices, one in the UK and one in the other EU country
- possible percentage of home office usage, i.e. I could be working from home for one entire month or should I better keep contact points once a week with the client on site?
- best practice for documenting business trips to clients in another EU country and how to claim expenses in a different currency if the client is actually registered in the UK
- general advise on taxation
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