OK, so my speakers weren't great...
But, having pulled them out, and searched on here, I was at a bit of a loss. The depth seems hopeless for what is a wide opening. 5" seemed to be the suggestion and - through sheer impatience more than anything - I had a look at Halfords speakers. This is when I realised I had a problem. The info available on the various (unknown to me) makes - depth, hole, etc, was rubbish. So I started looking online at what the best 5" speakers were and lost hours of my life I'll never get back.
Move on to this morning and I got scientific.
It means more if you see the picture:
The first circle indicates the largest magnet that will fit beside the GRP web, which is 28mm back from the face of the door in my car, and the second is the size of magnet that'll fit before the rusty steel lip which is 25mm from the face.
However, the door card (plastic moulding) is 15mm from the face of the door. So, you get a maximum of 15mm plus 25mm ie 40mm depth across the full width of the speaker aperture. Hmm. Yep, another 3-4 hours lost on the internet looking for a speaker that'd fit and that everyone hadn't rubbished.
In the end, I faced the outlook of feeling miserable all day for having failed, or going to Halfords and buying the best they had in 5".http://www.halfords.com/technology/car- ... l-speakers
SE6a needing lots of work...