Accrueing holiday pay through an agency. (office angels)?

Help, I was recently between jobs and decieded to temp for a month through office angels,
I was open with them from the start and explained that I was only available for 4 weeks as I would then be starting me new permanent position. I was told that I would accrue holiday at .385 for every week work, I worked four weeks and accrued 1.54 days holiday. I have now started at my permanent job and I have asked for my holiday to be paid (as agreed).
Office angels have now said that they will not pay my holiday because I only worked for four weeks and you have to work five to 鈥渁ctivate鈥?your holiday! They also said that their holiday year ended on the 30/09/07 and that all last years holiday has been wiped. I e-mailed Office Angels three times before the end of September to ask for the holiday pay, I also followed this up with phone calls. Is there anything I can do? I worked as agreed and no they want to stiff me out of holiday pay I鈥檝e earned, no-where on the t and c鈥檚 does it say that you have to work five weeks before your holiday is active and I was never told that this was the case. I know there is no union ofr temps but does any one know of anyone I can go to for help???

This sounds v shady as the right to annual leave accrues from day 1 of your employment.
See www.acas.gov.uk and ring their helpline which is v helpful.