> in fact the UK has been a net contributor to the EU for a long period of time
Your membership fee was lower (per-capita, per-GDP) than other countries. That membership fee has bought you services, the same services that other countries have been enjoying, and paying at a premium compared to the UK. The UK has been a member of the EU by its own decision for over 30 years. Nothing to complain about there. On the other hand, EU members which have been paying premium membership price should very seriously consider adding to the exit bill whatever rebates have been granted to the UK during all these years.
> As we are leaving the EU will we in some way get to reclaim some of the assets paid for over the period of time? Do we get the roof of the parliament in Strasbourg?
When I am renting an apartment, and I need to pay for something that needs repair, I do not ask for money back whenever I leave. There may be some assets that you have a right to claim a stake in, though. There are also some open bills. That is a matter of exit negotiations.
By the way, who is paying for the financial burden that the negotiations themselves are going to put in the EU? I hope that is also a matter of negotiations, and since it is a UK decision to leave (which we respect), the UK must contribute specially to those costs.
> And given the current alignment of rules I wouldn't imagine it would be a huge burden
1. Since there will not be automatic law alignment, we can not guarantee this long-term
2. There won't be a framework to enforce this, since the EU will have no jurisdiction in the UK, and vice versa. Creating a third-party enforcement framework seems too big of a burden.
> Once we've left, well paying associated costs may be a sensible thing to do, but that's for us to decide!
For you ... and for the EU. As said, I do not think it is in the interest of the EU to deal with issues at these level of detail with each potential partner. We already deal with this at the EU level, put it in to law, and let the common EU enforcement mechanisms do the management. No need to duplicate this structure for each partner and each scheme that our partners would like to enjoy.
A better solution, discussed at length, would be to negotiate access to the EU market (which includes these kind of schemes) with the UK. But this has already been ruled out by Theresa May, since it assumes acceptance of the four freedoms.