Wiper Delay

I have studied all the posts of wiper refurbishing and the delay repairs. has anyone any experience of fitting the electronic delay unit sold by, I think, Wadhams My delay stopped working last year, and I cannot get it off the car. Also I was warned that 'repairs are not always successful.' would fitting an electronic unit be a viable replacement?
I also have a circuit diag. of a delay unit from the internet. This simply has a n/o output that closes for each wipe. An the advantage that the delay time is variable. Anyone ever fitted such a device to a P6 3500S
Since the original delay, I am surprised how much I miss it.