Unfortunately the premise of the question, that the British used the same battle tactics in two subsequent wars, is absolutely incorrect and ignores evolution of tactics in both conflicts.

Although there are a number of legitimate criticisms that can be made of British tactics early in both wars as they adapted to two fundamentally different conflicts (and they did adapt, continually), in no way can these tactics be summarised as mindlessly charging machine guns.

There's a good answer in the Wiki from u/elos here that talks about the impact (and degrees of impact) of some of these tactical evolutions on the Western Front, but it's worthwhile noting that you'll find tactics were not necessarily varied or static one way or another across even a theatre or campaign.

That's before you consider differences in tactics between theatres (British tactics in the Middle Eastern theatre were obviously very different tactically from the Western Front by example). Examples even within a theatre are present of localised tactics varying considerably from the contemporary modus operandi - in 1916 on the first day of the Somme battle, the 36th (Ulster) Division action against the Schwaben Redoubt was a notable (and successful) example of abandonment of typical tactics in favour of adopting to local conditions. Another example of typical in-theatre tactics evolving according to local conditions is the approach to trench raiding, first performed by Canadians in the Messines area in 1917 that would later be famously formalised by Australians and New Zealanders in 1918 as "Peaceful Penetration".

Even within the Boer War, British tactics evolved and varied depending on local conditions. By war's end by way of example, some British units (Imperial contributions from Australia and New Zealand were almost exclusively comprised of Mounted Infantry) were composed primarily for mobility, in order to track down and pin Boer formations whilst the British systematically used brutal means to isolate and lock down Boer means of resupply. This represented a completely different approach by the British when compared to tactics employed at, say, Magersfontein or Spion Kop at the start of the war.

If you wish to read more, Thomas Pakenham's "The Boer War" is a good starting point on that conflict, although it's dated and there's quite possibly a range of alternatives you could refer to. A really quick web search pulls up a book I haven't read yet, "From Boer War to World War 1902-1914" by Spencer Jones. I've not read it, so can't speak to it, but given it covers pretty much this subject, it might be worth a look.

"Tommy" by Richard Holmes is a solid book on the nature of the British Army (or three armies as he suggests) in World War 1, particularly on the Western Front.