How do I know the window handle screw cap will fit my old handle?

The only way to be sure that it will fit is to find out which handle you have and then check that it is the correct model. Most customers send a picture on email to the Technical team to identify the handle and that way you can be sure.

I have ordered previously from you so will the spare handle caps still fit?

You can check the handle on the website and it will then be clear that the handle and cap haven't changed. The details of each screw cap will highlight the models it will fit.

How does the window handle cap fit?

It varies as some are sticky pads and some are a push fit with clip-in lugs.

I want a screw cover cap for the hidden hole on an espag handle as it looks unsightly when the handle is open?

In most cases you can't get a screw cover cap for this fixing hole as the hole is not only used for the screw fixing but also the sprung loaded push button mechanism. One manufacturer does make their handles with two caps but this is very rare - see W85 and W86 espag window handles.