Vauxhall Astra astra sportive 1.7cdti van over hearted & now has a tapping sound from engine

May have caused a camshaft cap to loosen off due to heat expansion ,if noise is from the top of the engine and ensure you have plenty of oil in it ,would check this first and possibly do an oil and filter change if it’s been really hot

If it overheated and you continued driving it could be a top end noise, but it could also be a piston or big end bearing difficult to say without hearing it ,sorry cant be more helpful .