Capital legacy won't protect your estate

Just get a life policy from one of the major insurance companies to cover the executor fees, add 15 percent for VAT. Appoint a trusted family member or a local law firm specialising in deceased estates. They do not have a national presence and they don't like paying out. Their business model is incentivised to not pay out. An insurer on the other hand is firstly a financial service provider. Or better yet allow those you leave your estate to select own executor locally. This will allow them to interview and screen best choice.