Nie.
Urlop (i zaplata za niego) przysluguje ci jak kazdemu innemu pracownikowi. Fakt ze pracujesz tu dla agencji nie ma nic do rzeczy. Jesli agencja ci nie laci (a pracowales tam dluzej niz miesiac) to idz do CAB.
Odpowiadalem juz na to pytanie i podawalem linki, pogrzeb w forum, na pewno znajdziesz te posty.
EDIT:
O, mam:
Your rights as an agency worker
Agency workers are usually considered to be ‘workers’, not ‘employees’. Workers’ main rights are:
paid holiday, rest breaks and limits on working time 
no unlawful deductions from wages 
the National Minimum Wage 
not to be discriminated against under any of the equality legislation 
http://www.direct.gov.uk/en/Employment/ ... G_10027514I drugie:
SECTION 7: PAID ANNUAL LEAVE
Every worker – whether part-time or full-time – covered by these regulations is entitled to 4.8 weeks (24 days if you work a five day week) pro-rata for those working part-time. This will increase to 5.6 weeks (28 days if you work a five day week) from 1 April 2009. 
http://www.berr.gov.uk/whatwedo/employm ... 28979.html