Contractor Among Contractors
Still gathering requirements...
1) It is a good idea to read up on the "stickiness" of UK tax residency, and the assessment procedure based on number of connections you hold. If I remember correctly, you need to watch the number of days you spend in the UK for at least 5 years after you become non-resident (happy to be corrected).
2) If you are UK tax resident, it doesn't matter where you live or where your company is based, if HMRC determine that you are exercising control over the company remotely.
3) Latvia, like many other countries, does not have tax law that treats control in this way. So if you are Latvian resident and control a U.K. company, there is little downside.
4) Social tax is a lot higher in Latvia, so a large salary is not an option (dividends better as you mentioned).
5) 2 companies in different tax jurisdictions with different corporate tax years (Latvia is the European Jan-Dec fiscal period, UK is bespoke) provide transfer pricing opportunities.
6) Also consider incorporating in Estonia, which has no corporation tax on profits, only on drawdown, and on that basis is an attractive holding destination for non-UK tax residents looking to park profits. Search on e-residency - everything can be managed remotely.