It might also be down to the filler being easier to rub down or the new blocks being better to use that the small lump I used to use or possibly that the paper doesn't clog up within a few rubs. I don't know but it is certainly better than I remember.
My next challenge is that I have surprisingly few opportunities to work on the car in the coming months as I am away most weekends between now and the summer when we go away for the month of August. I could get my head round going in the garage after work but the mess created and the agro in emptying the garage of all the bikes and clutter before I can start work means that the chances of that happening are slim, I must try harder. The other issue I have is that I need a few parts and I have no money left in the Healey fund which is a challenge. I'll work something out.
My plan is to do one panel at a time then remove it from the car and prime it before rubbing it down again then removing them again and re-priming and painting the inside in top coat before the final fit prior to painting the car Healey Blue. This is not the quickest approach but I don't want overspray on the car and I know that I'll get some if I try to paint the panels on the car.