Variable-length Figure Cipher Used by Gilbert Gifford?

Speaking of variable-length figure cipher mentioned yesterday, I found in my notebook file a possibly relevant record:

"The words in italics are in cipher, only partly deciphered. The cipher for the most part consists of figures which run on without a break, and are thus capable of various solutions, according as they are taken as single or double numbers; and this sometimes prevents the deciphering of one passage by the aid of another."
From: 'Appendix: January 1588', Calendar of State Papers Foreign, Elizabeth, Volume 21, Part 1: 1586-1588 (1927), pp. 661-671. URL: http://www.british-history.ac.uk/report.aspx?compid=74826&strquery=cipher Date accessed: 06 May 2013.

This note belongs to a letter from Stafford to Walsingham from January 1588, but may refer to an enclosed letter from Gilbert Gifford (under the pseudonym of Francis Hartley) to Thomas Phelippes (M. Wilsdon).
Inspection of the original manuscript is desired.