I’ve had a search through the old forum photos (must get them archived somewhere) and there are quite a lot of Merry Tiller photos but only a few relating to a dozer blade. I think these images posted here were originally by will haggle.
Although not good, I think underneath the fuzzy image below of the dozer blade it says “can be front or rear mounted” – may have to squint a bit…
http://vhgmc.co.uk/wp-content/uploads/2015/12/MT4.jpg
The last image also shows a front mounted blade.
sorry cannot be of any more help but it may be a guide.