Just in case anyone has a similar problem...
The boiler resolved itself and began working normally again. Still kept the appointment with npower; they did a flue test and adjusted the levels (as they had increased markedly but were still within parameters).
Most likely issue according to...
Thanks both. See what Npower say tomorrow but hopefully it won't be a difficult fix for them or Worcester. The light sequence is single red, then red and blue together. Hopefully they know what that means!
Hi and thanks for reading....
I have a Worcester 28i junior combi boiler - its about 12 months old. We had some problems during the recent cold snap and unfroze the pipes using the kettle solution given here. All working fine for the 3 weeks since.
Today, we've come home and the boiler is...