I hope it's OK to post this, but some of you might recall that there was a thread on here a while back about diurnal variation - the extent to which peak flow varies through the day & over a series of days, & the somewhat complicated Maths used to work it out. Myself & anjyil said we'd have a look & see if we could produce anything that might help, & have come up with a spreadsheet if anyone wants it.
Just to emphasise, we've done our best to work it all out, but it should really be seen as something to help & guide you - it's 100% NOT diagnostic & may very well have errors in it, but if anyone wants a copy, please message me & I will send it to you.
It's free - if you think it's worth anything, I'd far rather you donate to AsthmaUK!