Health and Education are manifestations of that sense of charity.
In which case over the past 150 years as the UK has been increasingly less religious and increasingly more secular there is no doubt that those manifestations of charity have massively increased. While we might worry about the strain on our education and healthcare systems, part of the reason is that more people than ever are benefiting to a greater degree from the health and educational services provided in the UK.
Charitable love is not just a warm feeling or emotion. It attends sacrificially to the needs of others and often that targeting is on a national collective level because that is the most effective way of meeting the needs of others.
Sure - so sacrificing your time to volunteer to help others, or sacrificing income, through charitable donations are clearly manifestations of charity using your definitions.
Tax systems will not go away but if an increasingly secular population has less charitable impulse
But you have absolutely no evidence for this hand waving assertion. Certainly over the past 20 years or so there is no evidence that 'an increasingly secular population has less charitable impulse' given that levels of volunteering and charitable donations (adjusted for inflation) haven't declined, despite a major decline in religiosity over the same time period.
So health and education are in part charitable activities funded by whatever taxation policy one votes for. An increasingly secular population has seemingly opted for taxation with a far lower charitable component.
No it hasn't - so although overall charitable donations have remained broadly constant over the past couple of decades, the amount donated to different type of charitable activity has shifted somewhat - away from religion and towards other causes, including health related and educational - so in effect we give the same overall, but more to health and education and less to religion.