I also doubt the likelihood of a two tier eurozone or the reversion to the peseta. Although you can never say never, at this stage it looks unlikely in the short to medium term. Even informed eurosceptics feel it is unlikely.
If it did happen I doubt whether it would be implemented in a planned and orderley way. More likely it would probably arise on the back of a major default, which would shake the financial markets to the core including our own. In such circumstances I doubt whether many people would be looking to invest in anything and the value of stocks/shares and housing in the UK and Spain would probably plunge.