Looks like I first bought in 2008. They then had a large rights issue which I tail swallowed and this seems to have massively increased my holding without me spending any more cash. I then seem to have purchased more during 2011 and 2012 at between 200 and 250p/share and I took up the 2017 rights at 345p/share, before top slicing in 2018 and 19.
My dividend history shows a cash dividend decrease of ~1/3 between 2008 and 9 with small increases in 2010 and 11 and then an almost 6 fold increase in 2012 (in cash terms) most of that seems to be accounted for by the share purchases made in 2011 and 2012 when it was yielding between 5.8 and 7.3%. So it looks like I made some very well timed purchases signalled by the high yield. The SGRO holding is showing an 836% gain, my best performing share by a long way.
Sadly, I missed out on Segro which might have been a good partner for my B. Land holdings back in the day when I had two representatives of each sector. I don't remember the reasons, but something about Segro put me off at the time and I never revisited. Looking at the yield, far too late now.
As regards trimming: the need to do so would be a fine thing! It hardly happens to me, which probably says much about my stock picking. I've trimmed Diageo and Astrazeneca once each. Some shares have been self trimming - like Carillion