Firstly, re-taking a place as a credible trading nation is a challenge. The world has changed from the days of the Empire, equally so from when the UK joined the Union in 1973. Alliances, disputes, wars and issues are varied, complex and volatile. Trade has changed. We live and trade in a world of digitisation, climate change, migration and technological advances across all sectors including Space needing traders to adapt to constantly changing circumstances.
Secondly, and in spite of the impression of Free Trade, the increase in documentary requirement and evidence belies the term. Export skills had not been needed for intra sales between the UK and the EU and so it is a steep learning curve.
And lastly… maintaining relationships with the EU. How we move forward as a country could temper of attitudes to negotiating and formalising agreements with the UK. Strategic groupings and individual countries may feel that the UK is a disruptor rather than a perfect partner.