To the north of the frontal boundary, low-level convergence and surface heating may allow one or  two heavy showers to develop during Tuesday afternoon / early evening. But given rather unimpressive mid-level lapse rates, suggest any showers will be largely stunted in vertical development and consequently very little (if any) lightning will occur.

Similarly, potential for a few showers to develop in the afternoon and early evening, though limited in vertical extent and hence very little lightning expected.

Scope for some medium-level destabilisation to occur on Tuesday evening and night, perhaps with a few showers - these could extend as far east as East Anglia / SE England by Wednesday morning. That said, depth of instability is limited, but with better mid-level lapse rates there could be some lightning - but point probability considered quite low.