No contract doesn't matter as she's been there for a year and a half so a contract is implied.
the only thing is the notice period obv, but again because she's been there more than a year they can't just sack her.
What does that mean then, implied? Basically that they cant just sack her? Does that also mean she has to give a standard notice period rather than just sod off when she is ready to leave?
If anybody at an equivalent level there does have a written contract then she has the same terms as them, if nobody does then she has 'standard' terms.
Obviously that would be up to an employment tribunal to interpret, but for notice when paid weekly: weeks notice, paid monthly: months notice.
And employment tribunals tend to err on the side of the employee, the threat of this should be enough to make them behave themselves as long as they realise just how expensive it is for a company to go through one.
The extent to which they tend to be on the side of the employee means that although technically she still has to give notice, it's unlikely anything would happen if she didn't.