If I were to invest assets in an account which I was told in advance was a "notice" account, I wouldn't expect to be able to access them at short notice.
Of course; you're absolutely right growstuff. And that's exactly the same as a property owner renting his house (asset) out to a tenant for an agreed length of time (fixed term tenancy) and then reviewing at the end of that fixed period as whether he wants to leave his investment where it is, or liquidate his assets (sell it). That's a fixed term tenancy. But why do you think that he shouldn't be allowed to sell his own property/ies if he decides he needs/wants to?
That's why I think we should move towards rental properties owned by housing associations (or similar), who know where they stand in law and don't regard the property they own as a liquid asset.
Firstly, properties are not classed as "liquid assets"; liquid assets are funds that are readily available in banks accounts and can be quickly converted into cold hard cash.
All of the properties that are owned by housing associations, or similar, are their "assets portfolio". They purchase properties, in exactly the same way as private individuals do - they just buy more of them. They rent them out to tenants, at a profit, in order to sustain their company, satisfy shareholders and be a sucessful and profitable business like any other business in the marketplace. If a property becomes "inequitable" (perhaps the necessary modernisation, or reparation to bring it up to standard, outweighs the rental profit ratio) they sell it - tenants or not.
The housing rental business, no matter who the landlord is, or how big or small their portfolio is, is a business out to make a profit. There is no largess in business - no matter what it's commodity is.