Officially, there is no chance of being kept on after the 11 months.
The last intake of temporary crew did a 6 month contract and were then offered LGW. So it could happen again but it is not guaranteed. A few of the ex-WW crew that went to LGW were quite vocal about the differences so therefore LGW management are voicing concern about taking ex-WW crew again. However, going by the recent crew shortages, they may not have choice. There is the 900 hour rule that may effect employability, which may be another reason why there are no guarantees.
It is highly doubtful that the current intake of WW temps will be kept on at WW. They would need to clear the hundreds of existing crew on transfer lists before that would happen. If there are vacanies at EF, there is no reason that they wouldn't be offered places there but again, transfer lists will need to be honoured first.