Mark,
Don't just stick with bikes if you have a balance problem
Although more expensive, and second hand ones are rarer, when you do your research, bo include electric trikes as well.
The other thing that may help is VAT
If you are registered as disabled, then unfortunatley you cannot claim VAT back on the bike / trike a these can be ridden by a "able" person and hence are not sufficiently modified, but some bits of kit and modifications can be claimed back
Don't just stick with bikes if you have a balance problem
Although more expensive, and second hand ones are rarer, when you do your research, bo include electric trikes as well.
The other thing that may help is VAT
If you are registered as disabled, then unfortunatley you cannot claim VAT back on the bike / trike a these can be ridden by a "able" person and hence are not sufficiently modified, but some bits of kit and modifications can be claimed back