The same rules apply for soletraders, partnerships and Limited Companies
You can claim back any train/tube/tram/bus/taxi fares, parking expenses, tolls etc that you incur for any business meetings away from your normal place of work.
When it comes to overnight stays and trips abroad, again you can claim for all expenses, e.g. train/air/taxi fares and accommodation costs so long as the trip “wholly and exclusively for business purposes”. People fall into the trap of thinking that it would be a good idea to tag a few days holiday on the end, or to take their spouse/partner, but in the eyes of the Revenue this immediately gives a trip dual purpose and, strictly speaking, none of the expense is allowable against profits.
If you have to stay overnight on a business trip you can claim the cost of an evening meal and your breakfast.
VAT can be claimed on any travel expenses where VAT receipts are obtained.
What You Can Claim As Business Expenses main page.