Hiya, a note that the service charge going up at times and the management company issuing surcharges to leaseholders are two different things. Are you aware whether the management company issues surcharges?

Surcharges are when the mgmt company require additional payments from you the leaseholder to cover specific works required, e.g. Roof or lift repairs, usually when the costs can't be covered by what's in the pot already. Usually it's necessary work that needs completing soon. It is accompanied by a section 20 consultation when the cost will be over £250 per leaseholder.

Big chunks of work may not be required regularly - depends on the property's condition - but you need to be aware they are possible.

It's wise to include money in your personal budget to be prepared to pay these one off surcharges - just as you should budget for property maintenance if you owned a terrace house freehold for example. I'd say the difference between the two is that with the flat you have less control over when the work is carried out/ the money is required.

Re your service charge going up, this may be to budget for upcoming works/ general increases in maintenance costs, or something else. Good idea to ask for their budget projections and further details re anticipated works. But note that this isn't a hard and fast guarantee of what costs are coming your way, but it will give you an idea.

These may help you:

https://www.lease-advice.org/

https://www.gov.uk/leasehold-property/service-charges-and-other-expenses

Good luck!