Worcester Greenstar Junior - reset button not working?

I have had the same problem as many on here, frozen condenser pipe - unblocked it from ice, let it settle overnight and it reset fine in the morning carried on working for nearly 2 days, but this evening it cut out whilst the heating was on - same problem frozen pipe again, cleared the blockage but now the reset button is doing nothing - have I overpressed it and need an engineer?... I am under contract with British Gas Homecare but they cannot come out for nearly 7 days due to Christmas/Bank hols HELP!!!!

Sam ST73
December 2010