Yes, it is possible to turn a four digit number into pounds and pence format in Excel. Here are the steps to do so:

1. Select the cells that contain the four digit numbers you want to convert.
2. Right-click on the selected cells and choose "Format Cells" from the menu.
3. In the "Format Cells" dialog box, select the "Number" tab.
4. In the "Category" list, choose "Custom".
5. In the "Type" field, enter the following format code: 0.00
6. Click "OK" to close the dialog box.

This will convert the four digit numbers into pounds and pence format. For example, the number 1234 will be displayed as 12.34.

If you have over 10,000 cells to change, you can use the "Format Painter" tool to quickly apply the same format to multiple cells. Here's how:

1. Select a cell that has the desired format (i.e. a cell that displays a number in pounds and pence format).
2. Click on the "Format Painter" button in the "Clipboard" group on the "Home" tab.
3. Click and drag over the cells you want to apply the format to.

This will quickly apply the pounds and pence format to all the selected cells.