Correct. Cross it out then sign next to the deletion. The seller is welcome to accept or reject the OTP without that clause.
Some compromise may be needed, but sale is only valid when both parties agree to all T&Cs.
Agents put clauses in their version of the OTP that suit them. However, the agent has a contract with the seller only, and no contract with the buyer. The OTP is an offer from the buyer to the seller, and if the seller accepts it, it becomes the contract between the seller and the buyer, a contract to which is the agent is
not a party.
When a buyer wants to make an offer, there is no obligation whatsoever to use the agent's OTP, and that OTP it is not, as some agents would have one believe, "just the standard thing". You can add and subtract any clauses freely. A hopeful buyer must specify the property properly, the name of the owner their own name, the price offered and the desired date of the sale. There are good, sensible reasons to have many other clauses, but they are not essential by law. Most important is to read and understand every clause, including what could go wrong if this aspect of the sale were not also specified in the OTP.
There is a possibility that if your OTP has had clauses struck from the agent's version, or is completely different, the agent may refuse to pass it on to the seller. That's a pity, if you really want to buy the property, but if, on the other hand, you're willing to buy only with your own version of the OTP, then an unwilling agent is a sign that something's not going to go well. If you have the details of the seller, you could send them your OTP directly, not through the agent, and see what happens.