some points to consider from pointers i have collected in the thread:

(i) most of CS do not consider unrelated experience so you are possibly a 'freshie' to them. (anything less than 2-3 years in relevant scrope is unrelated)
(ii) most of CS put more weight into your bachelor degree (i.e., brand and class)
(iii) most of CS do not consider masters in your pay for relatively new starters but it may help in your career progression in long-term.

no point arguing too much because they have a formula that they go by.

having said that, you should be paid according to your bachelor FCH. mind sharing if your bachelor is local, too?