The UK does get hail and frost. The question of whether your panels can handle both is worth answering properly rather than assuming everything is fine.
Hail: the test standard
The IEC 61215 standard covers the design qualification of crystalline silicon solar panels. The hail test fires steel balls of 25mm diameter at the panel surface at 23 metres per second (83 km/h) at eleven impact points. A passing panel shows no cracking, no cell breakage, and no significant power loss after impact.
UK hail is almost always below 25mm diameter. The hailstorms that make the news are typically 5mm to 15mm. Large hail events of 25mm or above do occur — mostly in central and southern England during summer convective storms — but they are rare. Standard panels from established manufacturers (JA Solar, DMEGC, Canadian Solar, Jinko) pass IEC 61215 and will survive typical UK hail without damage.
Frost: no problem at all
Frost does not damage solar panels. The operational temperature range of standard panels is typically -40°C to +85°C. UK winter temperatures do not come close to the lower limit. Snow on panels reduces generation while it sits there but causes no structural damage. Cold temperatures do increase panel open-circuit voltage above the 25°C datasheet figure — which matters for inverter compatibility (see our MPPT article) but causes no physical damage to the panel itself.
What does cause panel damage
Mechanical impact from objects other than hail — falling branches, tools dropped on the surface, golf balls in a bad location. These can crack the glass and are not covered by manufacturer warranties. Some home insurance policies cover solar panels for accidental damage. Check yours, particularly if panels are under trees or in an exposed position.
Salt corrosion on coastal installations: panels within 500 metres of the coast should have marine-grade anodised aluminium frames. Ask specifically about coastal rating when buying panels for exposed locations.