DH died last year and there are an embarrassing number of things I have never tried my hand at.
We also seem to have had a run of things going wrong in the house. The latest is a broken push button flush on the toilet.
So, I took it apart, took photos of the mechanism inside the cistern and went to the scary plumbers merchant with the bits. Asked him if he could sell me a new one. He had a good look but said they didn't appear to stock what I needed. I nearly left, but instead said "OK then what do I need to do" and maybe he felt sorry for me or maybe he remembered he was there to offer the customer some service
but he said if you bring a photo of the mechanism I'll find it for you. I'd already got that so there was no backing out for him!
He found the part I needed on line and I ordered it from Amazon (I know, but free next day delivery). It's arrived and I've fitted it and it works!
I know it's not much, but I am so pleased with myself. Maybe I can do this after all 
£10 v what, at least £80 if I'd called a plumber?