Suppose you have the following A record:
example.com. 3599 IN A 111.123.456.78
example.com. 3599 IN A 192.0.2.78
And these MX records:
example.com. 997 IN MX 10 mx01.1and1.co.uk.
example.com. 997 IN MX 10 mx00.1and1.co.uk.
example.com. 997 IN MX 10 mx01.1and1.co.uk.example.
example.com. 997 IN MX 10 mx00.1and1.co.uk.example.
And you then changed the IP address for the A record to a non 1&1 ip address (so that the website could be hosted on an external hosting), would that affect the MX records or mess up the email in any way?