Unless you're applying to Oxbridge, UCL, Imperial, Warwick, or Sheffield, you aren't going to be singled out due to your A Level choices. At those universities, ICT would generally be considered a less preferable subject, and they would be looking for strong performance in Maths and another preferred A Level (usually Physics or Further Maths) to compensate for this. Outside of those universities however, you'll most likely be fine. None of the other Russell Groups openly discriminate based on A Level choice, and tbh a strong performance in Maths alone will put you in a good position. Ultimately, if you're doing A Level Maths with one other facilitating subject, ICT as your third A Level will be totally fine in the majority of cases. If you still feel doubtful, make sure to email the universities you're interested in attending. Good luck!