You Do Need power plug adapter while traveling from Wales to Bangladesh.

Here is Why You Need An Adapter

The outlet and plug type used in Bangladesh are A, C, D, G and K and in Wales is G. This is how they look like.

Wales

In Wales, outlets of type G are in use.

Type G

Bangladesh

In Bangladesh, outlets of type A, C, D, G and K are in use.

Type A

Type C

Type D

Type G

Type K