Yes : you need to use the shopping cart facility rather than pay for each lot individually.
No : IB Stamps has one of the largest stocks of GB and British Colonial revenues in the world, so if you can't see what you want please email me with your requirements.
Yes : You can pay by personal cheque (UK banks only) or direct transfer or even cash (sterling only) Personal cheques should be made payable to IB Stamps Ltd. Direct transfer details will be sent on application.
The only reliable catalogue series is published by John Barefoot of York - these cover most of what I sell.