Questions are ongoing even after an evidence session with children's minister Nadhim Zahawi, held earlier this month by the House of Lords Secondary Legislation Scrutiny Committee, which today published its report.
The committee has been considering the DfE's decision to remove the statutory requirement on adoption agencies to register children who are waiting to be matched with adoptive parents.
Launched in 2001, the register was suspended at the end of March. It had been run since 2016 by CoramBAAF, one of the UK's biggest adoption agencies, via its Leeds-based matching service Adoption Match.
Key among the concerns raised about the Department for Education's plans for replacing the register, is that it was suspended before a replacement is ready, and there is no clear timetable - points also raised by Coram.
Committee chairman Lord Trefgarne has written to Nadhim Zahawi MP asking for further clarification by 31 May.
He asks: "Indeed, are you able to state whether there will be any improvements in the adoption arrangements for these children, either immediately or the longer term?"
Lord Trefgarne also asks for clarity over the fees paid by local authorities to alternative commercial registers, as well as the status of such companies.
The report states: "The committee remains unclear about the department's plans, timetable and budget for the replacement service.
"Whilst acknowledging the objective of trying to improve the service, the committee remains concerned by some of the potential implications of having ceased the adoption register before a replacement has been identified, and in particular the potential diminution of provision during this interim phase for those children who may be more difficult to place."
The report also questions why the DfE did not address an issue with local authorities' non-compliance with the register - cited by the department as one of the reasons for the suspension.
While the changes, according to the committee, "do not require the approval of the Houses", they could yet be debated in parliament.
The report states: "We are concerned by this apparent non-compliance with the statutory requirement and query why it had not been followed up at an earlier stage. Should this instrument be the subject of a motion for debate, the House may wish to press the minister further about this matter."
Giving evidence on 14 May, Zahawi outlined his vision for a new national register combining adoption and fostering, that would elevate the "voice of the child" in the matching process.
The committee also heard that almost all local authorities prefer to use the main commercial alternative to the register, Link Maker, to which they pay an annual fee.
The DfE has been approached for comment.