1) on the confirm page, look for the following tag:
<input type="hidden" name="currency_code" id="currency_code" value="USD" />
and change it to:
<input type="hidden" name="currency_code" id="currency_code" value="GBP" />
2) Using PayPal Standard, it will not configure the email receipt. PayPal Payments standard is a remote payment gateway, using a remote payment gate, you will need to rely on the gateway to send the receipt.
3) on the confirm page, find the following code:
<input type="hidden" name="return" id="return" value="" />
and set the full address for the return page:
<input type="hidden" name="return" id="return" value="http://www.mydomain.com/checkout_success.php" />