I've done a search and can't find my particular situation, so I'm stuck. If you can help me I'd appreciate it.

I've been living in Spain since 1999, I'm in Spain for the majority of the year . I have a Spanish SL company and intend to do some teaching contracts in the UK. I've been reading up about tax and IR35 but there seems to be different opinions and views about foreign companies/individuals. I pay a lot of tax in Spain (30% corp tax) about about 60% personal tax (include NI). Most of the Spanish company income is from the UK.

I spent less than 90 days a year in the UK (including travel days), so I am non-resident. I invoice through my Spanish company to UK companies. The UK company is treated as a Training Establishment by HMRC. I have no offices in the UK and I spend about 4 or 5 days doing a contract.

Should I be paying UK tax/NI on this UK income? Do I fall under IR-35? For the moment I am assuming I am liable for Spanish tax only. Am I making a mistake?

I've also read that their is a double-taxation agreement between Spain/UK with tax exempt status for teachers (DT17620 http://www.hmrc.gov.uk/manuals/dtmanual/dt1936.htm). So perhaps I should change my status to UK resident for the next 2 years. Anyone have any knowledge about this exemption?

Cheers
-Ruairi