We kept the caravan we had before the moho at a CaSSOA Gold site. The motorhome is about 1.5 metres longer than the old 'van and wouldn't fit our storage pitch. The CaSSOA site owners couldn't find us a suitable pitch in time and so we moved to a (much closer) non-CaSSOA site with locked gates, CCTV and operators who live onsite. We were paying just over £400 p.a. (£100 per quarter) and are now paying £365 per year (1 payment each year) in storage fees. However, the new site closes at 5:00 pm. each night except Sundays, when it closes at 4:00 pm; so we sometimes now have to spend an extra night out at a pub stop if we can't get back to storage in time.
Because we originally planned to stay with with the CaSSOA site, we got insurance quotes for keeping the moho at both facilities. Strangely, the CaSSOA Gold status didn't make much difference to our insurance premium (aboiut a tenner a year).