I have a 3yr old solo 30he. It was serviced a couple of months ago and had a new burner, insulation panel, seals and electrode. Since then it has been slow to ignite banging on ignition. With the outer door off the ignition spark is seen emerging from the electrode plate and sparking back across the ceramic to the lead connector. Another electrode has been tried and a new ignition and earth lead with no success. Baxi have nothing to offer other than wrapping insulation tape around the ceramic and lead connection which has cured it. Can it be anything else other than both electrodes being faulty and letting the current emerge before it gets to the spark gap?