Veneering experimentation

I have a large amount of veneer that I have accumulated over the years. I have occasionally used my stocks in smallish projects doing edge-banding or fixing flaws. I'm currently working on a keepsake box for my nephew and his fiancée for their forthcoming marriage in June.

I had some sapele veneer in strips about 6 feet long 10" wide and also some oak burr veneer so decided to try flattening the veneer and veneering the top of the box. This is essentially a piece of 9mm MDF cut to the size of the rabbets I had cut in the box upper sections.

I enquired on Woodtalk Online forum if anybody had any recipes for a veneer softener as the commercial softeners are not available here in the UK. The commercial ones in use in the US are SuperSoft 2 Veneer Softener or the other one "Veneer Softener/Tamer". The mailing costs were prohibitively high or there were export restrictions.