A solution, which is perfectly acceptable to HMRC, is to substitute some of the employe's pay with the childcare vouchers.
This should be done in time for HMRC to send out a self assessment tax return for the relevant year.
If you require immediate communication with HMRC you should request documents to be sent by facsimile.
The Adjudicator is a fair and unbiased referee whose recommendations are independent of HMRC.
You must register as self-employed with HMRC within three months, or you could pay a penalty.