Just had a great idea for my father's birthday present, and wondered if anyone (especially in the UK) has any idea where I can buy inexpensive tartan trews? Ideally they'd be in a variety of tartans. He's disabled and wouldn't feel comfortable in a kilt, but used to wear trews when I was a youngster in the Tartan.

Ideally in the UK, but not essential.

Many thanks
Graham.