Why not get together ?
All UK councils must have roughly similar needs; all are splunking huge sums to solutions providers.
I can't see why they don't club together and produce something that does what they need, then all use it. Sure it would cost an arm & leg and take several years, but after that they will save bucket loads. Yes: there is maintenance (need change, etc). Maybe it could be open sourced and let councils/... in other countries use it, add modules, submit patches, etc.
When all councils are using the same s/ware: exchange of information would be so much easier.