“Laundress El ptmva, cheque £12.” Key lost.
I think that this and the previous peculiar phrase on April 12 have been encrypted using a simple Caesar shift cipher. If we shift each letter along the alphabet by 7 letters (a to h, b to i, etc), then the April 12 phrase iexwyxk fr ptmva tgw uxeel becomes pledfer my watch and bells.
The word ptmva (watch) is repeated in today’s partially enciphered phrase, with El perhaps being the Latin et (and) with an uncrossed t.
Given yesterday’s entry referring to receipt of a cheque from Longmans, I think a reasonable interpretation of all this is that Stevens had a cash-flow problem: on the 10th, he “pledged my watch and Bell’s” at a pawnbroker in order to pay the rent on his house. After receiving the Longmans payment he was able to write a cheque for £12 to the pawnbroker in order to re-possess the watches and obtain sufficient cash to pay the laundress.